Consider the following example:

1) Create QFileSystemModel and attach it to a QTreeView
2) Create a subdirectory x1/x2/x3/x4
3) Expand the entire hierarchy x1->x2->x3->x4 in the QTreeView
4) Call QDir("x1").removeRecursively()

Result: removeRecursively() fails. In console I see

QFileSystemWatcher: FindNextChangeNotification failed for "C:\Users\krasu\AppData\Local\Temp\watcher-text\x1\x2\x3\x4" (Access denied.)

Using the attached sample project:

1) Compile and run
2) Click "Expand" multiple times
3) Click "Delete"

Result: You'll see an error message.