from http://bugs.musicbrainz.org/ticket/5324

Background:
First I've tagged the files (no tags on files yet and they're on some temp folder) and Picard renamed and moved the files.
Then I realized I didn't entered the disc information so I basicly drag dropped already tagged files to Picard. It recognized the album. I added the "discnumber" and "totaldiscs" from the details. Then pressed "Save Tags".
At this point the files were at "artist x/album a" directory. Normally I was expecting (according to my move file string) Picard to move the files to "artist x/album a/disc 01" folder, but apperantly it couldn't.
And instead of dropping the operation Picard continued and deleted the source files.
By the way in options I've also selected to move all remaining files and also I think I should mention that the album was a classical album so path name and track titles was long. And also the album name has chars like "œ" and "é" in it.

Picard Log:
E: <sip.voidptr object at 0x01A6DC10> 23:02:35 Traceback (most recent call last):
File "picard\util\thread.pyo", line 80, in generic_run_item
File "picard\file.pyo", line 151, in _save_and_rename
File "picard\file.pyo", line 305, in _move_additional_files
File "shutil.pyo", line 199, in move
File "shutil.pyo", line 91, in copy2
File "shutil.pyo", line 47, in copyfile
IOError: [Errno 2] No such file or directory: u"c:\\silme\\tagged
Hector Berlioz
La Damnation de Faust (Orchestre et Ch\u0153ur de l'Op\xe9ra de Lyon feat. conductor_ Kent Nagano) (1995)
disc 01
faust-01.jpg"

This error was repeated 14 (track count) times.