Is this an IMAP account? What provider? Does restarting your computer in Windows safe mode with Networking act the same?

RoadRunner is my ISP. None of the 3 accounts are IMAP. They are Roadrunner, Yahoo, and Gmail. When I ran in Safe Mode, it appeared to work correctly, but when I went back to normal mode, I still have to restart Thunderbird. Also this only started happening after I installed the lastest Thunderbird update.

Safe mode disables anti virus email checking, as well as "on access" scanning. So I think the issue will be with your anti virus program. Some things to try.

1. Create an exception in your anti virus and exempt Thunderbird's profile folders from on access scanning. Issues with Thunderbird and the anti virus arguing in the background over who gets to use the file are then prevented (you full scans should still include those folders.

1. Disable email scanning in your anti virus program

I changed my anti-virus program and have the same result. I am now using AVG. Again, when I exit Thunderbird and restart it, everything works fine.

I have disabled my AVG anti-virus and still have the problem. I always have to start Thunderbird and second time before I can delete or move messages. When I restart everything works fine. Are there any other suggestions?

I've been using Thunderbird since early this year and have had this issue all during that time. AVs are often blamed though I've noticed no consistency on which AV (if any) was in use. Also rebuilding profiles and mailboxes is often suggested - in my case I was told to rebuild a mailbox with zero messages and zero bytes in the file which seemed unlikely to do anything but I did anyway. (And it didn't help.)

Some people get the problem multiple times a day, some people are good for days or weeks. I once had the probably daily for 3 days, but now I've gone nearly a month without having it. It seems to be that way for others as well because they will often report that they "fixed it" by doing "X" but then days or weeks later they come back to the thread and say - nope I've still got it.

I was hoping to install TB on all my family's PCs but this one is holding me back. I hope someone figures it out.

Good luck!