All the repair function does is rebuild the MSF file. Maybe TB didn't rebuild it correctly. If not you can try repairing again. Of just delete the MSF file while TB is closed, and TB will recreate next time you access your inbox. To do that:

1. Go to Help > Troubleshooting Information, then click on Open Containing Folder. That will open Windows Explorer in your Thunderbird profile.
2. Close Thunderbird.
3. In your TB profile folder navigate to the folder that contains the folder for the account you're having trouble with. For example \hhvati19.default\Mail\pop.mail.yahoo.com\
4. There should be two files for each mail folder - Inbox, Inbox.msf, Sent, Sent.msf. Delete Inbox.msf.
   Do not delete the files without extensions. Those contain your actual messages.
5. Start Thunderbird, and open your Inbox.

It just happened again in the JUNK folder. None of the messages would show in the preview so I decided to repair the junk folder and when done I lost over 2000 junk messages. Not a big deal, but it continues to happen on each folder that is repaired. I have two inbox.msf files, one for each account I have. I will try and let you know!

That delete did not work. Had to remove the postdata.dat to recover the files.

That file is a HTTP send file... are you using an add-on to get your mail? Or did you mean popstate.dat and you have actually re downloaded your mail?

I first tried the inbox.msf file removal and that did nothing, so I removed the postdata.dat file and the messages returned, not all but most returned.

Not sure why this happens, but its the first time for me. Was it due to the last update? Don't want to deal with it again, so I hope not to have to repair any folders to prevent this from happening again. Having a business is tough enough, but then to lose all 190 messages that are in the inbox for a reason unknown is a PITA!

Where did your delete this postdata.dat file from. I can't even find one in my profile.

Well it happened again. Message was all garbled and I did the folder repair and again lost all my messages!! I searched for the postdata.dat and this time it was not there at all! What the heck is going on that I continue to lose messages after a folder repair and why can't I get them back this time! Might have to switch to another email client!! This stinks!

The answer for someone else in my mail this morning else nortons quarantining their inbox.

My Thunderbird files keep disappearing; file repair restores temporarily. This just started; I found a virus and had it removed so I am wondering if that caused it.

Under Local Folders I have: Trash Trash.msf Unssent Unsent.msf

Under Pop.verizon.net I have: Drafts Drafts.msf Inbox Inbox.mfs Sent Sent.mfs Trash Trash.mfs MsgFilterRules.dat PopState/dat

I don't understand why some of the folders are under the Pop.verizon.net and the others are under Local Folders.

I've never had this problem; I wonder if a systems restore would fix it