BinaryBoy's reply to howard251 #1766 @
One situation that can cause this is when a directory can't contain any more filenames. With long filenames, this typically happens at around 2000-3000 files. The "Stop if disk space under" option on the Files tab can also cause this to happen if triggered.
If you want to test whether the recent Privacy tab option are causing the problem, you could set them to Recycle and then check the Recycle bin if it happens again.