Guess the answer to this question is NO then!

I couldn't believe this bug when it happened and I googled and found how common it was. Losing all your emails without doing anything wrong at all would have to be one of the worst bugs in any software program - ever!

I'm a user like you and I haven't seen the bug yet. Can you give me a link?

I tried to restore From cache I copied one file to another directory. Using an add-on, ImportExportTool, I tried to import it. It said it was a corrupt mbox, I continued and the cache-file was imported. The one I "rescued" was empty. I then used RecoverDeletedMessages and it worked.

So you might as well try it

Cheers - if you google InBox messages deleted Thundebird you will find 100s of examples.

The mailbox is often corrupted if you compact after downloading and deleting too many messages - and you lose everything. Its a pretty serious bug.

Yes, but thats questions not bugs and mostly solved.

Often there is a virus protector that interfere. For them the whole folder, as its a single file, is infected if they found anything suspicious in one message and they therefore put folder in quarantine or delete it. This is why we urge people to make an exception for the TB profile in their virus protector.

As Inbox is the most used folder (file), every new message is entered at the end of that file and stays in there until you compact. We recommend to keep it very small and compacted.

A big inbox, many messages, one or all marked (as to be) deleted, when compacted has to do the same as a small inbox. Read a message state (if deleted or not) - copy the not-deleted to a new temp-file. And repeat until all not-deleted messages are copied then delete old inbox and rename temp-file to inbox. If the copying is interrupted, the compacting can start over again. That can lead to leftover temp-files filling up your disk. If inbox is small, its less risk this would happened and if it happens the temp-file would be smaller.

A corrupt message, whether it got corrupted on its way or not, can mess up the folder-file so compact cant find were the next message starts. Another reason to keep inbox small.

I recommend that you perform compacting when offline, as any try to download or sync your inbox might be a cause to you loosing messages. It shouldn't happened but anyway.

One other cause is many people doesn't understand IMAP. They delete messages on their phones and still expect them to be in TB on their pc.

TB has an experimental try on using filedir, thats a single file for each message, but that has its own problems.

AND MAKE BACKUPS.

It is pretty amazing that the software can fail so catastrophically on standard usage.

Best advice would be for Thunderbird users not to go on holidays!

Yeah its the software

JV2016 said

Question is - I can see all the cache files are still sitting there, with the date/time from when the issue happened. Is it possible to restore the inbox from the cache somehow?

Yes it is. It's what most people call a backup.

JV2016 said

Guess the answer to this question is NO then! I couldn't believe this bug when it happened and I googled and found how common it was. Losing all your emails without doing anything wrong at all would have to be one of the worst bugs in any software program - ever!

A high percentage of such cases is caused by antivirus software

I selected all messages in my inbox, then did SOMETHING ? and lost all, not in waste bin. What happened ? Can I recover the mails ? ( I was online and on the server all was gone too) Thanks a lot