Please provide more information:

• Who are your mail providers?
• IMAP accounts, or pop?
• What AV software are you running?

Based on a previous question: Person said setting were same as I mentioned which implies it is IMAP. e-mail server is Charter.net, now part of Spectrum.

Do not know what Anti-Virus product is being used.

re: Automatically downloads new e-mails from my internet service and deletes everything that was already in my in-box. The first time it did that the old e-mails were completely lost. Since then they have gone into the trash, so they can be retrieved,

• 'Tools' > 'Activity Manager'

Does the 'Activity Manager' say: 'Moved X messages from Inbox to Deleted'?

In a previous question you mentioned this: had the presence of mind to forward them to my Yahoo Mail were I stashed them in a new folder - then forgot I'd done that. It dawned on me the other day and I retrieved them (leaving them on Yahoo Mail too, as backup.)

Do you still have something set up in Charter/Spectrum webmail which is popping emails to a yahoo account? If yes, then after email is sent to yahoo account then server may be deleting the popped/fowarded email, hence putting it in Trash. So when IMAP thunderbird connects with server, it can only show what is on server. So all those popped off to yahoo emails are now in server Trash, so Thunderbird shows them in the Trash.

Thanks for the replies.

Wayne, my internet provider is Spectrum (nee Charter.) It's an IMAP account. My AV is Symantec/Norton 360.

Toad, I have never had anything set up to share e-mails with my Yahoo account. The only way something gets into my Yahoo Mail is if I manually forward it there. Which I hardly ever do, only if I want to save a copy somewhere else. Unless, of course, it was sent there directly by the sender, which hardly ever happens because I don't use Yahoo Mail for anything much. (Maybe I should - Yahoo seems to have pretty much eliminated spam, which Spectrum/Charter has not even come close to doing.)

E-mails sent to Yahoo Mail as well as those downloaded by Thunderbird remain on my Charter webmail, though I suppose they might eventually be deleted if I didn't delete them myself.

No, Activity Manager doesn't say that. It doesn't say anything.

Nothing is ever in the webmail/server trash, at least not for more than a few minutes. I'm sort of compulsive about cleaning out the trash and I do it every time I check my mail when I leave the webmail page.

If Thunderbird was to delete anything that's not still in the webmail inbox, it would be hard to understand why it's coded to do that. I don't think the good folks at Mozilla are that dumb. Surely they don't expect us all to leave everything on the webmail page after we download it to the local computer. If all Thunderbird did was mirror the webmail page there'd be no reason to have Thunderbird. I need a local e-mail client so I can save e-mails that might be lost when Charter webmail has one of it's hiccoughs and dumps things or just goes down and can't be accessed.

Oddly, when I opened Thunderbird just now to look at the settings to check that it's an IMAP account and not POP, all my Charter mail was downloaded but the few e-mails already in the Inbox did not automatically delete. For the first time. So now we can add inconsistency to the mystery. Curiouser and curiouser, as Alice said...

Auggghhh!!!

It did it again!

As a test, I downloaded my latest messages from webmail and Thunderbird immediately deleted all the messages already in the Inbox. And like the first time, it didn't move them to the trash; it just deleted them completely.

Problem solved.

I've deleted Thunderbird and got another e-mail client.

Thanks for your time and effort.

If you are using an Imap mail account then all emails are actually stored on the server - aka what you see when you logon to webmail account. If you delete emails via the webmail account then they are auto deleted from an imap account when it access and synchronise with server. No Imap account has folders that are totally independent copies. That is not a Thunderbird thing - it is identical for any email client using an IMAP connection.

All Imap accounts work by synchronising the imap folders with the server folders, so they display exactly the same. It means you can use more than one device eg: additional computers, phones or logon via webmail and you always get the same emails in the same folders.

Only POP mail accounts can get access to a server Inbox and download a copy to your computer pop mail account Inbox. There is no synchronisation involved, so a Pop account Inbox can be considered independent of server. If you did a POP dowonload and then accessed webmail and deleted emails it would not effect the POP account.

So in answer to your statement: Surely they don't expect us all to leave everything on the webmail page after we download it to the local computer.

The answer is Yes you must leave it on the server - visible in webmail - if you use an IMAP setup.

If you want to see emails in Imap accounts then you must have those emails still visible on the server, otherwise the reason you cannot see them in an Imap account is because you have logged on to the webmail account and deleted them. That would also explain why the 'Activity Manager' is not saying it deleted them.

Mick99, I hope you have understood what I've said.

The reason for your loss of emails in the IMAP account was due to you deleting them from the server via the webmail account.

If you want to have a completely independent copy - so you can delete stuff off server and it does not effect anything you have already downloaded, then you must create and setup a POP mail account. You cannot simply convert an Imap into a POP.

Then it would work as you expect it to work in Thunderbird and indeed in any email client.

Your data loss was not due to Thunderbird. It was because you did not understand the difference between a Pop account and an Imap account.

I'm posting this info because if you use another email client and you set up an Imap account, you will have the same problem.

All the best.