The error message attachment did not happen in the original post.

That sort of error is usually due t the file being locked when thunderbird tries to write to it, or the disk. The primary cause of this contention is an anti virus product that is either poorly coded, slow or overloaded on a slow machine.

Try disabling your anti virus and then see if there is enough disk space.

Disabling my Anti-Virus software does not help, I had also fixed that problem a long time ago.

Are you using: (A) 'File' > Compact Folders' OR (B) right click on the specific folder and use 'Compact' ?

suggest you use (B) method

Try repairing the index first and then using method (B) above. Right click on folder and select 'Properties' click on 'Repair folder' click on 'OK (B) right click on the specific folder and use 'Compact' ?

Sorry, but folder repair did not work.

What I did to solve my problem was this:

1. 1. Create a new local folder.
2. 2. Moved email messages in groups to the new folder until I hit the email message that was causing a problem.
3. 3. The message in error I had to leave behind, I could not copy it or move it.
4. 4. Renamed the bad folder and renamed the new one to the name I wanted.
5. 5. Fixed any message filters that used the bad folder, renaming the folder causes message filters to change.
6. 6. I could not delete the folder from within Thunderbird, so I had to exit and delete it by hand.

So far, that appears to have fixed the problem.

Al Nims

Can you retrieve the bad folder?? (backup, recycle bin, etc)

It would be nice to see the message that was causing the problem.

I was never able to do a backup, it got an I/O error.

ajnims said

I was never able to do a backup, it got an I/O error.

That would indicate the physical media you are storing your data in is probably failing. Total loss will probably be the end result. It might be time to upgrade or pay a technician.