WDSEML file are just not complete mails, or at least that is my understanding. I don't have them as I use Thunderbird to find my mail not the Windows search with I find inferior.

You could try renaming one as say test.eml and dragging it into a folder in Thunderbird and see if it appears and is what you think it should be. That is drag into Thunderbird not a file system folder.

Thank you Matt!

I ended up discovering that these files are files visualization of windows7 to search the archives of the Thunderbird.

However, I also discovered that I missed the messages corresponding to these files. The corresponding files from Thunderbird simply disappeared. I tried several tools such as undelete / unerase and these files appear as neither deleted files. Somehow they were erased and overwritten.

I found that files with the extension wdseml can be renamed to eml and read like a message, but the attachments were lost.

I believe some updating Thunderbird may have caused this, since a recent update occurred. The date of this update is the same date of multiple files still present (see the MS-Explorer), precisely the date given by my lack of posts.

This tragedy upsets/saddens me much. I ended up losing almost 50,000 messages, all stored and organized by topics since 2004! At least I can recover the text of these messages, even without its attachments.

There is not anything in your anti virus quarantine is there? The inbox folder in Thunderbird is a file called inbox. The same goes for all folders, a like named file exists. (Not many files)