if you create multiple "New folder" via explorer and if you set 0 permissions on one of them, then creating more "New folder" via explorer fails. It fails partly silently, I've also seen it fail with access denied error on the client. If you press F5 on the client before, then it seems to work though. Quite weird behaviour - I tried to reproduce this on a local NTFS filesystem, couldn't see such errors there. This needs some more investigations...