t_mrc-ct If disappeared mail still existed (and if you are remember mail's title or message), you may find it by Global Search (search field on Mail toolbar).
To find out why this problem is occured, I need more detailed information:
How you get new mail? (Recieved automatically or manually? Do you use 'Get Mail' button?, shortcut key? or another way?)
Do you have any thought about why 2 mails are remained. recieved time, tag, unread or filtering setting...?
The mail is gone. I attempted to search using universal search, including all subfolders. I also looked at the actual file size and it had dropped to 232 k or something like that. The two remaining emails were the 'new' emails that I heard come in. Mostly, it checks automatically every minute or so...and I have several filters which sort incoming mail into different subfolder. or leaves it in the main folder if it doesn't go to any subfolder. The only thing out of the ordinary was a brief net outage right before I noticed the issue, because when I heard the mail come in, I knew the net was back. I had just updated to the newest version within the last couple of days.
I also checked my settings and it was not set to remove mail to create disk space after a certain period of time. I googled online and at least one other person had reported what appears to be the same issue three months ago
t_mrc-ct I still not figure out why this problem occured. But it look like folder compacting bug.
Can you check the following preference setting on Config Editor?
mail.purge.ask
If this preference is set to 'false', I recommend it change to 'true'. It can not resolve this issue, but you can get alert dialog before compacting. It gives you a backup chance.
If this preference is already setting to true and you never saw Compacting dialog, this bug may not related to compacting...
I'll have to check it when I go to my workshop. I'm at home today and do not have remote access to that machine from here. I'm assuming access to the config editor is pretty much the same as this: https://support.mozillamessaging.com/en-US/kb/config-editor for Tenfourbird?
t_mrc-ct Yes. Usage of config editor is same as Thunderbird.
It was set to false.....so now I have set it to true. I tried to see if there were any log files which might help, but was unable to find anything other than an out of date filter log.
t_mrc-ct I hope this bug is prevented by this workaround.
If Compacting dialog is displaying too frequently, you can change compaction threshold higher. See How can I configure compaction?
Error Console may logging compaction error:
Menubar > Tools > Error ConsoleBut, Error Console's log is cleared on application quit timing. So related log have already gone...
Tenfourbird
Was away from my computer for a few, had a brief net outage, net came back, heard email, went to look, suddenly ONLY 2 emails in entire main inbox. All email in subfolders is still there, it is only the actual inbox. I looked in the trash, checked the actual files in the thunderbird folder in the user folder, and it's gone...doesn't seem to have been moved to any other folder either. Don't think I did anything that could have caused it. I'm using an emac 1.42 ghz with 1 gb ram, running Tiger. Luckily, I have copies of all of these, or should, on my home machine, as it's set to leave the files on the server when I check on this machine (work). I am assuming I cannot recover the emails at this point, but just upgraded to this version in last couple of days. afraid it could happen again.