Lost songs when add album art.

When I try to add cover to my songs from file *.jpg, some of my songs (.m4a - ALAC) have problem and they become *.tmp (i.e TMPD409.tmp). Now how can I get my songs back from the tmp files?
Thank you so much if you can help me.
Sorry for my English.

You can try to rename the *.tmp files back to *.mp4.

Did this happen with v2.46?

It works!!! :w00t:. I still have to retype my files' name but it is no problem. Thank you so much. I haven't seen this problem with v2.46.

you could open a cmd window in the top folder and enter a command like

ren /s *.tmp *.mp4
this should rename the tmp-files with an mp4 extension - and MP3tag should read them again.

Funny thing - I had the same issue with mp3s. I was embedding album art and mp3tag had some problems with few files (there was an error shown on screen), when I checked these problematic files i noticed, that all of them was renamed to *.tmp files with cleared tags. Funny but true.

Could it be that you had WMP running at the same time (or the media center) which could have watched that folder and opened the file as it detected an alteration?This could then have locked the file for writing.