Strange Behavior During Tag Writing

I have Windows 7 on a healthy, well functioning computer. I have been going through a big folder to edit all of my files and then I started experiencing some weird things...

Once, I noticed that after I added Album Art, as it was saving the tag data, all of the selected files' TITLE fields changed to be the same as the first file. This has happened three times.

Then, at different periods, when I was saving tag data for multiple files, it would say it couldn't find a specific file. I'd go to the folder to see what was wrong, and the file would be gone. In the folder location, the file would be gone. Instead, there would be an abnormally large text file. When I open the text file, it is a bunch of jibberish with what looks like the file information at the bottom; maybe the original file was converted into a text file? I looked all over the drive for the original file with no avail; the file was just obliterated. Luckily, I have a backup of everything.. whew.

Anyway, I was more throwing this up because I didn't see anything similar in the search and I thought it could be a bug? Unfortunately I was not able to get it to duplicate another time for a screen shot.

What happens if you replace the current filename extension with mp3 again?

I still would try a harddisk scan to make sure there is nothing evil going on.
Also, make sure that while you edit the files no instance of WMP is running (or any other program that indexes modifications in such audio files).
To me it looks as though some simultaneous access causes the problems.

i cannot say anything to the mysterious title duplication.

I didn't change the extension because after I noticed the files disappearing, I quickly replaced them with my backup. That is a good idea though... If it happens again I will remember to give that a try.

And I never use WMP, I stick with f00bar for my music, but when I'm doing editing, I don't have anything else open besides Windows Explorer and Mp3tag. And it is peculiar because it only happened two or three times.

And the title duplication sure was strange, I'm going to be doing a big batch of tag writing again today so hopefully I can replicate these issues at will.

Thank you for your input, Ohrenkino!