• Start Windows in safe mode with networking enabled - https://support.microsoft.com/en-us/help/12376/windows-10-start-your-pc-in-safe-mode
• Still In Windows safe mode, start Thunderbird in Troubleshoot Mode - https://support.mozilla.org/en-US/kb/troubleshoot-mode-thunderbird

Does problem change?

The notification system had been broken, so asking you again to post more detail.

I will try your recommendation today and let you know if it works. In the meantime, here's more information on the problem. This happens every time I use Thunderbird. Today I started reading through my emails and got about three done. My settings are to automatically open the next email when I move or delete the current one. Today, I read the 1440 and pressed delete. It highlighted the next email and hung as seen here.

I also have Thunderbird set up to sync with Gmail. All the folders were previously down in my Local Folders, but I moved them all back to Gmail when I started having problems with Thunderbird. I was afraid I would lose all my saved emails if Thunderbird was broken.

Thunderbird seems to hang sometimes when I move an email to a different folder (including trash). I guessing this has something to do with threading while syncing with gmail.

... So, I need to end this in Task Manager. I'll give you a screen shot of that as well.

Do you have an Anti-Virus product which is allowed to scan all incoming email/documents and also allowed to scan any file you open?

The non responsiveness may well be the Anti-Virus program constantly checking every file you open. Basically it takes over control for short periods before handing it back to Thunderbird.

Suggest you access the Anti-Virus and make your Thunderbird profile folder exempt from any scanning. After all, you have an imap account and it can only display whatever is on server and if Anti-Virus decided it did not like something and tried to 'fix' the mbox file, you stand a good chance of losing all emails in that folder and what's worse, losing emails off the server when it synchronised with server. Then you will be reliant on any backup which would need importing into 'Local Folders' account before trying to slowly get it all back onto the server.

Then see if this improves performance.

I notice you have a load of subfolders to your Inbox. When you move an email out of Inbox into another folder, that 'moved' or 'deleted' email gets 'marked as deleted' and 'hidden', but in reality, it is still in the 'Inbox' mbox file.

You need to make sre the 'Inbox' gets cleaned up to reduce it's size. Either manually right click on 'Inbox folder and select 'Compact' on a regular basis OR you can also set up the account to expunge the Inbox upon Exit.

• Account Settings:
• Select 'Server Settings' for the imap account
• Bottom right under 'Message Storage'
• Select checkbox 'Clean up (Expunge) Inbox on Exit'

1. My antivirus is the Microsoft built in. I made sure it's not checking every email. 2. I'm sure this is not just a slow performance problem, because I let it sit for four hours one day. It never came back. 3. I have automatic compact turned on, but I did turn on cleanup on exit as well. That didn't solve the problem. 4. While I was messing around in the settings, I noticed it is archiving everything to an All Mail folder. I turned that off and compacted that folder, since I never use it. 5. Voila! I have been able to read all of my email two days in a row without it hanging! Hopefully that did the trick.

> I noticed it is archiving everything to an All Mail folder. I turned that off

Where exactly did you make that change? (I am not aware of such a setting in Thunderbird)

How many messages were, or are, in the All Mail folder?

By the way, it just hung up again. I was reading the emails in my Bills folder, deleting some and moving some to another folder.

There are 9271 messages in the all mail folder at the moment (after restarting).

xxxx@gmail.com / account settings / copies & folders / Message Archives (Keep message archives in: Other: All Mail on xxxx@gmail.com)

... and in the amount of time it took to write this post, I read one email and it hung again while moving it to trash.

9271 messages is not an extreme amount of messages, such that it should cause problems.

The starting point really is https://wiki.mozilla.org/Thunderbird:Testing:Memory_Usage_Problems and the first ~10 steps are the easiest. Please let us know what you find.

I finally found time to dig thru the debugging site from the last message. It seems like reinstalling Thunderbird solved the problem. I can read an email, delete it or move it to a folder, and move on to the next email really fast. It's not hanged yet today. I think it's fixed.