It would be great if when Mp3Tag can't access a file because it's in use, the options presented to the user read: "Abort / Retry / Ignore".
Abort would cancel the whole operation. For example, if the user selected to rename the files using the tags, you could either stop the process at the file that's in use, or even undo the previous renaming because there was an error in the process.
Retry would try to access the file again. Sometimes I'm distracted enough to be playing a file and trying to edit it in Mp3Tag at the same time. With this, I could just stop my player and click Retry and everything would be alright.
Ignore would just skip the file that can't be written to, and continue with the next one.
As far as I know, this is standard windows-application behaviour. It would be nice to see this implemented in Mp3Tag too.
Thanks for your time,
noroom