diff --git a/src/blockstore/implementations/versioncounting/VersionCountingBlockStore.cpp b/src/blockstore/implementations/versioncounting/VersionCountingBlockStore.cpp
index 000131b4..3262e2fc 100644
--- a/src/blockstore/implementations/versioncounting/VersionCountingBlockStore.cpp
+++ b/src/blockstore/implementations/versioncounting/VersionCountingBlockStore.cpp
@@ -11,7 +11,7 @@ namespace blockstore {
 
 #ifndef CRYFS_NO_COMPATIBILITY
         void VersionCountingBlockStore::migrateFromBlockstoreWithoutVersionNumbers(BlockStore *baseBlockStore, const bf::path &integrityFilePath) {
-            std::cout << "Migrating file system for integrity features..." << std::flush;
+            std::cout << "Migrating file system for integrity features. This can take a while..." << std::flush;
             KnownBlockVersions knownBlockVersions(integrityFilePath);
             baseBlockStore->forEachBlock([&baseBlockStore, &knownBlockVersions] (const Key &key) {
                 auto block =  baseBlockStore->load(key);