I keep getting the message "Not responding" and I can't move, delete, send, or get new messages.
It seems like Thunderbird is overloaded - it locks up and I get the message "Not responding". I have to wait sometimes a minute or two, sometimes longer, before I can proceed to scroll thru my messages or delete a message (the functions most affected) but sometimes to reply or forward. It looks up my entire email.
ప్రత్యుత్తరాలన్నీ (3)
Start your computer in safe mode with network support and see if Thunderbird works normal.
I wasn't sure how to put my computer in safe mode. I looked it up on the web, but I'm not able to follow their instructions. It doesn't seem to be happening as much recently, so maybe I can live with it.
Starting in safe mode should not be that difficult. The process depends on your operating system. Safe mode starts up without your antivirus and that is the usual case of what you describe.