diff --git a/app/src/main/java/sushi/hardcore/droidfs/ChangePasswordActivity.kt b/app/src/main/java/sushi/hardcore/droidfs/ChangePasswordActivity.kt
index cba6598..5d8bc79 100644
--- a/app/src/main/java/sushi/hardcore/droidfs/ChangePasswordActivity.kt
+++ b/app/src/main/java/sushi/hardcore/droidfs/ChangePasswordActivity.kt
@@ -20,6 +20,7 @@ import sushi.hardcore.droidfs.adapters.SavedVolumesAdapter
 import sushi.hardcore.droidfs.fingerprint_stuff.FingerprintPasswordHashSaver
 import sushi.hardcore.droidfs.util.*
 import sushi.hardcore.droidfs.widgets.ColoredAlertDialogBuilder
+import java.io.File
 import java.util.*
 
 class ChangePasswordActivity : BaseActivity() {
@@ -80,9 +81,25 @@ class ChangePasswordActivity : BaseActivity() {
         super.onActivityResult(requestCode, resultCode, data)
         if (resultCode == Activity.RESULT_OK) {
             if (requestCode == PICK_DIRECTORY_REQUEST_CODE) {
-                if (data != null) {
-                    val path = PathUtils.getFullPathFromTreeUri(data.data, this)
-                    edit_volume_path.setText(path)
+                if (data?.data != null) {
+                    if (PathUtils.isTreeUriOnPrimaryStorage(data.data)){
+                        val path = PathUtils.getFullPathFromTreeUri(data.data, this)
+                        if (path != null){
+                            edit_volume_path.setText(path)
+                        } else {
+                            ColoredAlertDialogBuilder(this)
+                                .setTitle(R.string.error)
+                                .setMessage(R.string.path_from_uri_null_error_msg)
+                                .setPositiveButton(R.string.ok, null)
+                                .show()
+                        }
+                    } else {
+                        ColoredAlertDialogBuilder(this)
+                            .setTitle(R.string.warning)
+                            .setMessage(R.string.change_pwd_on_sdcard_error_msg)
+                            .setPositiveButton(R.string.ok, null)
+                            .show()
+                    }
                 }
             }
         }
@@ -93,37 +110,52 @@ class ChangePasswordActivity : BaseActivity() {
         if (rootCipherDir.isEmpty()) {
             Toast.makeText(this, R.string.enter_volume_path, Toast.LENGTH_SHORT).show()
         } else {
-            changePassword(null)
+            if (!File(rootCipherDir).canWrite()){
+                ColoredAlertDialogBuilder(this)
+                    .setTitle(R.string.warning)
+                    .setMessage(R.string.change_pwd_cant_write_error_msg)
+                    .setPositiveButton(R.string.ok, null)
+                    .show()
+            } else {
+                changePassword(null)
+            }
         }
     }
 
     private fun changePassword(givenHash: ByteArray?){
-        object : LoadingTask(this, R.string.loading_msg_change_password){
-            override fun doTask(activity: AppCompatActivity) {
-                val newPassword = edit_new_password.text.toString().toCharArray()
-                val newPasswordConfirm = edit_new_password_confirm.text.toString().toCharArray()
-                if (!newPassword.contentEquals(newPasswordConfirm)) {
-                    stopTaskWithToast(R.string.passwords_mismatch)
-                } else {
+        val newPassword = edit_new_password.text.toString().toCharArray()
+        val newPasswordConfirm = edit_new_password_confirm.text.toString().toCharArray()
+        if (!newPassword.contentEquals(newPasswordConfirm)) {
+            Toast.makeText(this, R.string.passwords_mismatch, Toast.LENGTH_SHORT).show()
+        } else {
+            object : LoadingTask(this, R.string.loading_msg_change_password) {
+                override fun doTask(activity: AppCompatActivity) {
                     val oldPassword = edit_old_password.text.toString().toCharArray()
                     var returnedHash: ByteArray? = null
-                    if (usf_fingerprint && checkbox_save_password.isChecked){
+                    if (usf_fingerprint && checkbox_save_password.isChecked) {
                         returnedHash = ByteArray(GocryptfsVolume.KeyLen)
                     }
                     var changePasswordImmediately = true
-                    if (givenHash == null){
+                    if (givenHash == null) {
                         val cipherText = sharedPrefs.getString(rootCipherDir, null)
-                        if (cipherText != null){ //password hash saved
+                        if (cipherText != null) { //password hash saved
                             stopTask {
                                 fingerprintPasswordHashSaver.decrypt(cipherText, rootCipherDir, ::changePassword)
                             }
                             changePasswordImmediately = false
                         }
                     }
-                    if (changePasswordImmediately){
-                        if (GocryptfsVolume.changePassword(rootCipherDir, oldPassword, givenHash, newPassword, returnedHash)) {
+                    if (changePasswordImmediately) {
+                        if (GocryptfsVolume.changePassword(
+                                rootCipherDir,
+                                oldPassword,
+                                givenHash,
+                                newPassword,
+                                returnedHash
+                            )
+                        ) {
                             val editor = sharedPrefs.edit()
-                            if (sharedPrefs.getString(rootCipherDir, null) != null){
+                            if (sharedPrefs.getString(rootCipherDir, null) != null) {
                                 editor.remove(rootCipherDir)
                                 editor.apply()
                             }
@@ -133,17 +165,20 @@ class ChangePasswordActivity : BaseActivity() {
                                 val newSavedVolumesPaths = oldSavedVolumesPaths.toMutableList()
                                 if (!oldSavedVolumesPaths.contains(rootCipherDir)) {
                                     newSavedVolumesPaths.add(rootCipherDir)
-                                    editor.putStringSet(ConstValues.saved_volumes_key, newSavedVolumesPaths.toSet())
+                                    editor.putStringSet(
+                                        ConstValues.saved_volumes_key,
+                                        newSavedVolumesPaths.toSet()
+                                    )
                                     editor.apply()
                                 }
-                                if (checkbox_save_password.isChecked && returnedHash != null){
-                                    fingerprintPasswordHashSaver.encryptAndSave(returnedHash, rootCipherDir){ _ ->
+                                if (checkbox_save_password.isChecked && returnedHash != null) {
+                                    fingerprintPasswordHashSaver.encryptAndSave(returnedHash, rootCipherDir) { _ ->
                                         stopTask { onPasswordChanged() }
                                     }
                                     continueImmediately = false
                                 }
                             }
-                            if (continueImmediately){
+                            if (continueImmediately) {
                                 stopTask { onPasswordChanged() }
                             }
                         } else {
@@ -158,8 +193,10 @@ class ChangePasswordActivity : BaseActivity() {
                     }
                     Arrays.fill(oldPassword, 0.toChar())
                 }
-                Arrays.fill(newPassword, 0.toChar())
-                Arrays.fill(newPasswordConfirm, 0.toChar())
+                override fun doFinally(activity: AppCompatActivity) {
+                    Arrays.fill(newPassword, 0.toChar())
+                    Arrays.fill(newPasswordConfirm, 0.toChar())
+                }
             }
         }
     }
diff --git a/app/src/main/java/sushi/hardcore/droidfs/CreateActivity.kt b/app/src/main/java/sushi/hardcore/droidfs/CreateActivity.kt
index 25a55fd..d9b9081 100644
--- a/app/src/main/java/sushi/hardcore/droidfs/CreateActivity.kt
+++ b/app/src/main/java/sushi/hardcore/droidfs/CreateActivity.kt
@@ -5,12 +5,9 @@ import android.content.Intent
 import android.os.Build
 import android.os.Bundle
 import android.view.View
+import android.widget.Toast
 import androidx.appcompat.app.AppCompatActivity
 import kotlinx.android.synthetic.main.activity_create.*
-import kotlinx.android.synthetic.main.activity_create.checkbox_remember_path
-import kotlinx.android.synthetic.main.activity_create.checkbox_save_password
-import kotlinx.android.synthetic.main.activity_create.edit_password
-import kotlinx.android.synthetic.main.activity_create.edit_volume_path
 import kotlinx.android.synthetic.main.toolbar.*
 import sushi.hardcore.droidfs.explorers.ExplorerActivity
 import sushi.hardcore.droidfs.fingerprint_stuff.FingerprintPasswordHashSaver
@@ -19,6 +16,7 @@ import sushi.hardcore.droidfs.widgets.ColoredAlertDialogBuilder
 import java.io.File
 import java.util.*
 
+
 class CreateActivity : BaseActivity() {
     companion object {
         private const val PICK_DIRECTORY_REQUEST_CODE = 1
@@ -53,91 +51,129 @@ class CreateActivity : BaseActivity() {
         super.onActivityResult(requestCode, resultCode, data)
         if (resultCode == Activity.RESULT_OK) {
             if (requestCode == PICK_DIRECTORY_REQUEST_CODE) {
-                if (data != null) {
-                    val path = PathUtils.getFullPathFromTreeUri(data.data, this)
-                    edit_volume_path.setText(path)
+                if (data?.data != null) {
+                    if (PathUtils.isTreeUriOnPrimaryStorage(data.data)){
+                        val path = PathUtils.getFullPathFromTreeUri(data.data, this)
+                        if (path != null){
+                            edit_volume_path.setText(path)
+                        } else {
+                            ColoredAlertDialogBuilder(this)
+                                .setTitle(R.string.error)
+                                .setMessage(R.string.path_from_uri_null_error_msg)
+                                .setPositiveButton(R.string.ok, null)
+                                .show()
+                        }
+                    } else {
+                        ColoredAlertDialogBuilder(this)
+                            .setTitle(R.string.warning)
+                            .setMessage(R.string.create_on_sdcard_error_msg)
+                            .setPositiveButton(R.string.ok, null)
+                            .show()
+                    }
                 }
             }
         }
     }
 
     fun onClickCreate(view: View?) {
-        object: LoadingTask(this, R.string.loading_msg_create){
-            override fun doTask(activity: AppCompatActivity) {
-                val password = edit_password.text.toString().toCharArray()
-                val passwordConfirm = edit_password_confirm.text.toString().toCharArray()
-                if (!password.contentEquals(passwordConfirm)) {
-                    stopTaskWithToast(R.string.passwords_mismatch)
-                } else {
-                    rootCipherDir = edit_volume_path.text.toString()
-                    val volumePathFile = File(rootCipherDir)
-                    var goodDirectory = false
-                    if (!volumePathFile.isDirectory) {
-                        if (volumePathFile.mkdirs()) {
-                            goodDirectory = true
-                        } else {
-                            stopTaskWithToast(R.string.error_mkdir)
-                        }
-                    } else {
-                        val dirContent = volumePathFile.list()
-                        if (dirContent != null){
-                            if (dirContent.isEmpty()) {
+        rootCipherDir = edit_volume_path.text.toString()
+        if (rootCipherDir.isEmpty()) {
+            Toast.makeText(this, R.string.enter_volume_path, Toast.LENGTH_SHORT).show()
+        } else {
+            val password = edit_password.text.toString().toCharArray()
+            val passwordConfirm = edit_password_confirm.text.toString().toCharArray()
+            if (!password.contentEquals(passwordConfirm)) {
+                Toast.makeText(this, R.string.passwords_mismatch, Toast.LENGTH_SHORT).show()
+            } else {
+                object: LoadingTask(this, R.string.loading_msg_create){
+                    override fun doTask(activity: AppCompatActivity) {
+                        val volumePathFile = File(rootCipherDir)
+                        var goodDirectory = false
+                        if (!volumePathFile.isDirectory) {
+                            if (volumePathFile.mkdirs()) {
                                 goodDirectory = true
                             } else {
-                                stopTaskWithToast(R.string.dir_not_empty)
+                                stopTask {
+                                    ColoredAlertDialogBuilder(activity)
+                                        .setTitle(R.string.warning)
+                                        .setMessage(R.string.create_cant_write_error_msg)
+                                        .setPositiveButton(R.string.ok, null)
+                                        .show()
+                                }
                             }
                         } else {
-                            stopTaskWithToast(R.string.listdir_null_error_msg)
-                        }
-                    }
-                    if (goodDirectory) {
-                        if (GocryptfsVolume.createVolume(rootCipherDir, password, GocryptfsVolume.ScryptDefaultLogN, ConstValues.creator)) {
-                            var returnedHash: ByteArray? = null
-                            if (usf_fingerprint && checkbox_save_password.isChecked){
-                                returnedHash = ByteArray(GocryptfsVolume.KeyLen)
-                            }
-                            sessionID = GocryptfsVolume.init(rootCipherDir, password, null, returnedHash)
-                            if (sessionID != -1) {
-                                var startExplorerImmediately = true
-                                if (checkbox_remember_path.isChecked) {
-                                    val oldSavedVolumesPaths = sharedPrefs.getStringSet(ConstValues.saved_volumes_key, HashSet()) as Set<String>
-                                    val editor = sharedPrefs.edit()
-                                    val newSavedVolumesPaths = oldSavedVolumesPaths.toMutableList()
-                                    if (oldSavedVolumesPaths.contains(rootCipherDir)) {
-                                        if (sharedPrefs.getString(rootCipherDir, null) != null){
-                                            editor.remove(rootCipherDir)
-                                        }
+                            val dirContent = volumePathFile.list()
+                            if (dirContent != null){
+                                if (dirContent.isEmpty()) {
+                                    if (volumePathFile.canWrite()){
+                                        goodDirectory = true
                                     } else {
-                                        newSavedVolumesPaths.add(rootCipherDir)
-                                        editor.putStringSet(ConstValues.saved_volumes_key, newSavedVolumesPaths.toSet())
-                                    }
-                                    editor.apply()
-                                    if (checkbox_save_password.isChecked && returnedHash != null){
-                                        fingerprintPasswordHashSaver.encryptAndSave(returnedHash, rootCipherDir){ _ ->
-                                            stopTask { startExplorer() }
+                                        stopTask {
+                                            ColoredAlertDialogBuilder(activity)
+                                                .setTitle(R.string.warning)
+                                                .setMessage(R.string.create_cant_write_error_msg)
+                                                .setPositiveButton(R.string.ok, null)
+                                                .show()
                                         }
-                                        startExplorerImmediately = false
                                     }
-                                }
-                                if (startExplorerImmediately){
-                                    stopTask { startExplorer() }
+                                } else {
+                                    stopTaskWithToast(R.string.dir_not_empty)
                                 }
                             } else {
-                                stopTaskWithToast(R.string.open_volume_failed)
+                                stopTaskWithToast(R.string.listdir_null_error_msg)
                             }
-                        } else {
-                            stopTask {
-                                ColoredAlertDialogBuilder(activity)
-                                    .setTitle(R.string.error)
-                                    .setMessage(R.string.create_volume_failed)
-                                    .setPositiveButton(R.string.ok, null)
-                                    .show()
+                        }
+                        if (goodDirectory) {
+                            if (GocryptfsVolume.createVolume(rootCipherDir, password, GocryptfsVolume.ScryptDefaultLogN, ConstValues.creator)) {
+                                var returnedHash: ByteArray? = null
+                                if (usf_fingerprint && checkbox_save_password.isChecked){
+                                    returnedHash = ByteArray(GocryptfsVolume.KeyLen)
+                                }
+                                sessionID = GocryptfsVolume.init(rootCipherDir, password, null, returnedHash)
+                                if (sessionID != -1) {
+                                    var startExplorerImmediately = true
+                                    if (checkbox_remember_path.isChecked) {
+                                        val oldSavedVolumesPaths = sharedPrefs.getStringSet(ConstValues.saved_volumes_key, HashSet()) as Set<String>
+                                        val editor = sharedPrefs.edit()
+                                        val newSavedVolumesPaths = oldSavedVolumesPaths.toMutableList()
+                                        if (oldSavedVolumesPaths.contains(rootCipherDir)) {
+                                            if (sharedPrefs.getString(rootCipherDir, null) != null){
+                                                editor.remove(rootCipherDir)
+                                            }
+                                        } else {
+                                            newSavedVolumesPaths.add(rootCipherDir)
+                                            editor.putStringSet(ConstValues.saved_volumes_key, newSavedVolumesPaths.toSet())
+                                        }
+                                        editor.apply()
+                                        if (checkbox_save_password.isChecked && returnedHash != null){
+                                            fingerprintPasswordHashSaver.encryptAndSave(returnedHash, rootCipherDir){ _ ->
+                                                stopTask { startExplorer() }
+                                            }
+                                            startExplorerImmediately = false
+                                        }
+                                    }
+                                    if (startExplorerImmediately){
+                                        stopTask { startExplorer() }
+                                    }
+                                } else {
+                                    stopTaskWithToast(R.string.open_volume_failed)
+                                }
+                            } else {
+                                stopTask {
+                                    ColoredAlertDialogBuilder(activity)
+                                        .setTitle(R.string.error)
+                                        .setMessage(R.string.create_volume_failed)
+                                        .setPositiveButton(R.string.ok, null)
+                                        .show()
+                                }
                             }
                         }
                     }
+                    override fun doFinally(activity: AppCompatActivity) {
+                        Arrays.fill(password, 0.toChar())
+                        Arrays.fill(passwordConfirm, 0.toChar())
+                    }
                 }
-                Arrays.fill(password, 0.toChar())
-                Arrays.fill(passwordConfirm, 0.toChar())
             }
         }
     }
diff --git a/app/src/main/java/sushi/hardcore/droidfs/OpenActivity.kt b/app/src/main/java/sushi/hardcore/droidfs/OpenActivity.kt
index c1908a1..192d957 100644
--- a/app/src/main/java/sushi/hardcore/droidfs/OpenActivity.kt
+++ b/app/src/main/java/sushi/hardcore/droidfs/OpenActivity.kt
@@ -7,8 +7,16 @@ import android.os.Bundle
 import android.view.MenuItem
 import android.view.View
 import android.widget.AdapterView.OnItemClickListener
+import android.widget.Toast
 import androidx.appcompat.app.AppCompatActivity
+import kotlinx.android.synthetic.main.activity_change_password.*
+import kotlinx.android.synthetic.main.activity_create.*
 import kotlinx.android.synthetic.main.activity_open.*
+import kotlinx.android.synthetic.main.activity_open.checkbox_remember_path
+import kotlinx.android.synthetic.main.activity_open.checkbox_save_password
+import kotlinx.android.synthetic.main.activity_open.edit_password
+import kotlinx.android.synthetic.main.activity_open.edit_volume_path
+import kotlinx.android.synthetic.main.activity_open.saved_path_listview
 import kotlinx.android.synthetic.main.toolbar.*
 import sushi.hardcore.droidfs.adapters.SavedVolumesAdapter
 import sushi.hardcore.droidfs.explorers.ExplorerActivity
@@ -82,52 +90,81 @@ class OpenActivity : BaseActivity() {
         super.onActivityResult(requestCode, resultCode, data)
         if (resultCode == Activity.RESULT_OK) {
             if (requestCode == PICK_DIRECTORY_REQUEST_CODE) {
-                if (data != null) {
-                    val path = PathUtils.getFullPathFromTreeUri(data.data, this)
-                    edit_volume_path.setText(path)
+                if (data?.data != null) {
+                    if (PathUtils.isTreeUriOnPrimaryStorage(data.data)){
+                        val path = PathUtils.getFullPathFromTreeUri(data.data, this)
+                        if (path != null){
+                            edit_volume_path.setText(path)
+                        } else {
+                            ColoredAlertDialogBuilder(this)
+                                .setTitle(R.string.error)
+                                .setMessage(R.string.path_from_uri_null_error_msg)
+                                .setPositiveButton(R.string.ok, null)
+                                .show()
+                        }
+                    } else {
+                        ColoredAlertDialogBuilder(this)
+                            .setTitle(R.string.warning)
+                            .setMessage(R.string.open_on_sdcard_warning)
+                            .setPositiveButton(R.string.ok, null)
+                            .show()
+                    }
                 }
             }
         }
     }
 
     fun onClickOpen(view: View?) {
+        rootCipherDir = edit_volume_path.text.toString()
+        if (rootCipherDir.isEmpty()) {
+            Toast.makeText(this, R.string.enter_volume_path, Toast.LENGTH_SHORT).show()
+        } else {
+            if (!File(rootCipherDir).canWrite()){
+                ColoredAlertDialogBuilder(this)
+                    .setTitle(R.string.warning)
+                    .setMessage(R.string.open_cant_write_warning)
+                    .setCancelable(false)
+                    .setPositiveButton(R.string.ok) { _, _ -> openVolume() }
+                    .show()
+            } else {
+                openVolume()
+            }
+        }
+    }
+
+    private fun openVolume(){
         object : LoadingTask(this, R.string.loading_msg_open){
             override fun doTask(activity: AppCompatActivity) {
-                rootCipherDir = edit_volume_path.text.toString() //fresh get in case of manual rewrite
-                if (rootCipherDir.isEmpty()) {
-                    stopTaskWithToast(R.string.enter_volume_path)
-                } else {
-                    val password = edit_password.text.toString().toCharArray()
-                    var returnedHash: ByteArray? = null
-                    if (usf_fingerprint && checkbox_save_password.isChecked){
-                        returnedHash = ByteArray(GocryptfsVolume.KeyLen)
-                    }
-                    sessionID = GocryptfsVolume.init(rootCipherDir, password, null, returnedHash)
-                    if (sessionID != -1) {
-                        var startExplorerImmediately = true
-                        if (checkbox_remember_path.isChecked) {
-                            savedVolumesAdapter.addVolumePath(rootCipherDir)
-                            if (checkbox_save_password.isChecked && returnedHash != null){
-                                fingerprintPasswordHashSaver.encryptAndSave(returnedHash, rootCipherDir) { _ ->
-                                    stopTask { startExplorer() }
-                                }
-                                startExplorerImmediately = false
-                            }
-                        }
-                        if (startExplorerImmediately){
-                            stopTask { startExplorer() }
-                        }
-                    } else {
-                        stopTask {
-                            ColoredAlertDialogBuilder(activity)
-                                .setTitle(R.string.open_volume_failed)
-                                .setMessage(R.string.open_volume_failed_msg)
-                                .setPositiveButton(R.string.ok, null)
-                                .show()
-                        }
-                    }
-                    Arrays.fill(password, 0.toChar())
+                val password = edit_password.text.toString().toCharArray()
+                var returnedHash: ByteArray? = null
+                if (usf_fingerprint && checkbox_save_password.isChecked){
+                    returnedHash = ByteArray(GocryptfsVolume.KeyLen)
                 }
+                sessionID = GocryptfsVolume.init(rootCipherDir, password, null, returnedHash)
+                if (sessionID != -1) {
+                    var startExplorerImmediately = true
+                    if (checkbox_remember_path.isChecked) {
+                        savedVolumesAdapter.addVolumePath(rootCipherDir)
+                        if (checkbox_save_password.isChecked && returnedHash != null){
+                            fingerprintPasswordHashSaver.encryptAndSave(returnedHash, rootCipherDir) { _ ->
+                                stopTask { startExplorer() }
+                            }
+                            startExplorerImmediately = false
+                        }
+                    }
+                    if (startExplorerImmediately){
+                        stopTask { startExplorer() }
+                    }
+                } else {
+                    stopTask {
+                        ColoredAlertDialogBuilder(activity)
+                            .setTitle(R.string.open_volume_failed)
+                            .setMessage(R.string.open_volume_failed_msg)
+                            .setPositiveButton(R.string.ok, null)
+                            .show()
+                    }
+                }
+                Arrays.fill(password, 0.toChar())
             }
         }
     }
diff --git a/app/src/main/java/sushi/hardcore/droidfs/explorers/BaseExplorerActivity.kt b/app/src/main/java/sushi/hardcore/droidfs/explorers/BaseExplorerActivity.kt
index c8fc145..c9e90f2 100644
--- a/app/src/main/java/sushi/hardcore/droidfs/explorers/BaseExplorerActivity.kt
+++ b/app/src/main/java/sushi/hardcore/droidfs/explorers/BaseExplorerActivity.kt
@@ -194,7 +194,9 @@ open class BaseExplorerActivity : BaseActivity() {
                 }
             }
             total_size_text.text = getString(R.string.total_size, PathUtils.formatSize(totalSize))
-            explorerAdapter.notifyDataSetChanged()
+            runOnUiThread {
+                explorerAdapter.notifyDataSetChanged()
+            }
         }.start()
     }
 
diff --git a/app/src/main/java/sushi/hardcore/droidfs/util/PathUtils.java b/app/src/main/java/sushi/hardcore/droidfs/util/PathUtils.java
index 523fc52..bef2ea2 100644
--- a/app/src/main/java/sushi/hardcore/droidfs/util/PathUtils.java
+++ b/app/src/main/java/sushi/hardcore/droidfs/util/PathUtils.java
@@ -6,7 +6,9 @@ import android.net.Uri;
 import android.os.storage.StorageManager;
 import android.provider.DocumentsContract;
 import android.provider.OpenableColumns;
+
 import androidx.annotation.Nullable;
+
 import java.io.File;
 import java.lang.reflect.Array;
 import java.lang.reflect.Method;
@@ -81,24 +83,35 @@ public class PathUtils {
         return new DecimalFormat("#,##0.#").format(size/Math.pow(1024, digitGroups))+" "+units[digitGroups];
     }
 
+    public static Boolean isTreeUriOnPrimaryStorage(Uri treeUri){
+        String volumeId = getVolumeIdFromTreeUri(treeUri);
+        if (volumeId != null) {
+            return volumeId.equals(PRIMARY_VOLUME_NAME) || volumeId.equals("home") || volumeId.equals("downloads");
+        } else {
+            return false;
+        }
+    }
+
     private static final String PRIMARY_VOLUME_NAME = "primary";
     @Nullable
-    public static String getFullPathFromTreeUri(@Nullable final Uri treeUri, Context con) {
+    public static String getFullPathFromTreeUri(@Nullable Uri treeUri, Context context) {
         if (treeUri == null) return null;
-        String volumePath = getVolumePath(getVolumeIdFromTreeUri(treeUri),con);
-        if (volumePath == null) return File.separator;
-        if (volumePath.endsWith(File.separator))
-            volumePath = volumePath.substring(0, volumePath.length() - 1);
-        String documentPath = getDocumentPathFromTreeUri(treeUri);
-        if (documentPath.endsWith(File.separator))
-            documentPath = documentPath.substring(0, documentPath.length() - 1);
-        if (documentPath.length() > 0) {
-            if (documentPath.startsWith(File.separator))
-                return volumePath + documentPath;
-            else
-                return volumePath + File.separator + documentPath;
+        if ("content".equalsIgnoreCase(treeUri.getScheme())) {
+            String volumePath = getVolumePath(getVolumeIdFromTreeUri(treeUri),context);
+            if (volumePath == null) return null;
+            if (volumePath.endsWith(File.separator))
+                volumePath = volumePath.substring(0, volumePath.length() - 1);
+            String documentPath = getDocumentPathFromTreeUri(treeUri);
+            if (documentPath.endsWith(File.separator))
+                documentPath = documentPath.substring(0, documentPath.length() - 1);
+            if (documentPath.length() > 0) {
+                return path_join(volumePath, documentPath);
+            }
+            else return volumePath;
+        } else if ("file".equalsIgnoreCase(treeUri.getScheme())) {
+            return treeUri.getPath();
         }
-        else return volumePath;
+        return null;
     }
 
     private static String getVolumePath(final String volumeId, Context context) {
@@ -117,7 +130,6 @@ public class PathUtils {
                 Object storageVolumeElement = Array.get(result, i);
                 String uuid = (String) getUuid.invoke(storageVolumeElement);
                 Boolean primary = (Boolean) isPrimary.invoke(storageVolumeElement);
-
                 if (primary && PRIMARY_VOLUME_NAME.equals(volumeId))
                     return (String) getPath.invoke(storageVolumeElement);
                 if (uuid != null && uuid.equals(volumeId))
diff --git a/app/src/main/res/layout/activity_change_password.xml b/app/src/main/res/layout/activity_change_password.xml
index ca7ca28..d9655b0 100644
--- a/app/src/main/res/layout/activity_change_password.xml
+++ b/app/src/main/res/layout/activity_change_password.xml
@@ -143,7 +143,7 @@
                 android:layout_marginHorizontal="@dimen/action_activity_button_horizontal_margin"
                 android:layout_marginBottom="@dimen/action_activity_button_margin_bottom"
                 android:onClick="onClickChangePassword"
-                android:text="@string/change_volume_password"
+                android:text="@string/change_password"
                 style="@style/button"/>
 
         </LinearLayout>
diff --git a/app/src/main/res/layout/activity_create.xml b/app/src/main/res/layout/activity_create.xml
index 812ed8e..7488313 100644
--- a/app/src/main/res/layout/activity_create.xml
+++ b/app/src/main/res/layout/activity_create.xml
@@ -114,7 +114,7 @@
                 android:layout_height="@dimen/action_activity_button_height"
                 android:layout_marginHorizontal="@dimen/action_activity_button_horizontal_margin"
                 android:onClick="onClickCreate"
-                android:text="@string/create_volume"
+                android:text="@string/create"
                 style="@style/button"/>
 
         </LinearLayout>
diff --git a/app/src/main/res/layout/activity_open.xml b/app/src/main/res/layout/activity_open.xml
index 3dd0170..edb1336 100644
--- a/app/src/main/res/layout/activity_open.xml
+++ b/app/src/main/res/layout/activity_open.xml
@@ -102,7 +102,7 @@
                 android:layout_marginHorizontal="@dimen/action_activity_button_horizontal_margin"
                 android:layout_marginBottom="@dimen/action_activity_button_margin_bottom"
                 android:onClick="onClickOpen"
-                android:text="@string/open_volume"
+                android:text="@string/open"
                 style="@style/button"/>
 
         </LinearLayout>
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index 12fa7e5..a9db081 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -1,8 +1,11 @@
 <resources>
     <string name="app_name">DroidFS</string>
-    <string name="open_volume">OPEN A VOLUME</string>
-    <string name="create_volume">CREATE A VOLUME</string>
-    <string name="change_volume_password">CHANGE VOLUME PASSWORD</string>
+    <string name="open_volume">Open a volume</string>
+    <string name="create_volume">Create a volume</string>
+    <string name="change_volume_password">Change a volume\'s password</string>
+    <string name="open">Open</string>
+    <string name="create">Create</string>
+    <string name="change_password">Change password</string>
     <string name="password">Password:</string>
     <string name="password_confirm">Password (confirmation):</string>
     <string name="volume_path">Volume Path:</string>
@@ -163,4 +166,11 @@
     <string name="choose_filter">Choose filter</string>
     <string name="filters_warning">Filters can only be applied to reduced quality images. If you want to take high definition photos, do not apply any filters.</string>
     <string name="timer_empty_error_msg">Please enter a numeric value</string>
+    <string name="path_from_uri_null_error_msg">Failed to retrieve the selected path.</string>
+    <string name="create_cant_write_error_msg">DroidFS doesn\'t have write access to this path. Please try another location.</string>
+    <string name="create_on_sdcard_error_msg">DroidFS can\'t write on removable SD cards, please select a path on internal storage.</string>
+    <string name="open_on_sdcard_warning">DroidFS can\'t write on removable SD cards. You will only have read-only access to the volumes therein.</string>
+    <string name="open_cant_write_warning">DroidFS doesn\'t have write access to this path. You will only have read-only access to this volume.</string>
+    <string name="change_pwd_cant_write_error_msg">DroidFS doesn\'t have write access to this path. You can try to move the volume to a writable location.</string>
+    <string name="change_pwd_on_sdcard_error_msg">DroidFS can\'t write on removable SD cards, please move the volume to internal storage.</string>
 </resources>