URGENT! It turns out that it had duplicated every message in my Inbox - is it a bug? Should I avoid using Thunderbird? Thankyou!

What is the exact error message you get?

What's your account type - POP or IMAP?

How do your determine messages are duplicated if you don't see those "New E-mails" in your Inbox?

Thankyou so much for replying. There was no error message - just e-mails piling in. They eventually stopped (at 1934 "New" messages in Inbox), at which point I was able to see that every msg in the Inbox had been duplicated. I've run a virus scan, which picked up something (an "NSIS" virus - I can't give you the full name, as the software deleted it), but I haven't the foggiest if this is related to Thunderbird I deduped, but have done nothing else. At the moment it appears to be running as normal, but am worried it may occur again. It is a POP account. Thanks again.

How frequently do you compact your folders? You should do that regularly. Are you keeping old messages in the Inbox? You should not do that, since it was not meant to be used that way. You can move messages to new folders to store them, or archive them.

• http://kb.mozillazine.org/Compacting_folders
• http://kb.mozillazine.org/Keep_it_working_%28Thunderbird%29