diff --git a/src/db/update/Container.cxx b/src/db/update/Container.cxx
index 1be6ace29..b1474df90 100644
--- a/src/db/update/Container.cxx
+++ b/src/db/update/Container.cxx
@@ -46,12 +46,11 @@ UpdateWalk::UpdateContainerFile(Directory &directory,
 	{
 		const ScopeDatabaseLock protect;
 		contdir = MakeVirtualDirectoryIfModified(directory, name,
-							 info);
+							 info,
+							 DEVICE_CONTAINER);
 		if (contdir == nullptr)
 			/* not modified */
 			return true;
-
-		contdir->device = DEVICE_CONTAINER;
 	}
 
 	const auto pathname = storage.MapFS(contdir->GetPath());
diff --git a/src/db/update/VirtualDirectory.cxx b/src/db/update/VirtualDirectory.cxx
index de1d50695..5183374c5 100644
--- a/src/db/update/VirtualDirectory.cxx
+++ b/src/db/update/VirtualDirectory.cxx
@@ -23,7 +23,8 @@
 
 Directory *
 UpdateWalk::MakeVirtualDirectoryIfModified(Directory &parent, const char *name,
-					   const StorageFileInfo &info) noexcept
+					   const StorageFileInfo &info,
+					   unsigned virtual_device) noexcept
 {
 	Directory *directory = parent.FindChild(name);
 
@@ -32,7 +33,9 @@ UpdateWalk::MakeVirtualDirectoryIfModified(Directory &parent, const char *name,
 		if (directory->IsMount())
 			return nullptr;
 
-		if (directory->mtime == info.mtime && !walk_discard) {
+		if (directory->mtime == info.mtime &&
+		    directory->device == virtual_device &&
+		    !walk_discard) {
 			/* not modified */
 			return nullptr;
 		}
@@ -43,5 +46,6 @@ UpdateWalk::MakeVirtualDirectoryIfModified(Directory &parent, const char *name,
 
 	directory = parent.MakeChild(name);
 	directory->mtime = info.mtime;
+	directory->device = virtual_device;
 	return directory;
 }
diff --git a/src/db/update/Walk.hxx b/src/db/update/Walk.hxx
index 03efe0d4c..ac7a5bd5b 100644
--- a/src/db/update/Walk.hxx
+++ b/src/db/update/Walk.hxx
@@ -141,10 +141,14 @@ private:
 	 * exists already and is unmodified.
 	 *
 	 * The caller must lock the database.
+	 *
+	 * @param virtual_device one of the DEVICE_* constants
+	 * specifying the kind of virtual directory
 	 */
 	Directory *MakeVirtualDirectoryIfModified(Directory &parent,
 						  const char *name,
-						  const StorageFileInfo &info) noexcept;
+						  const StorageFileInfo &info,
+						  unsigned virtual_device) noexcept;
 
 	Directory *DirectoryMakeChildChecked(Directory &parent,
 					     const char *uri_utf8,