Is anyone else having problems with Thunderbird 6.0, or is it just me?

I get messages to say a draft can't be saved, or the sent copy can't be saved... I can't delete an email because it's being used someplace else... emails that are open (in a separate window) mysteriously close on their own...

It's never consistent, and the problem vanishes with the next email.  The self-closing window is the one I'm seeing most often.

All this since I upgraded recently, when prompted to.  I have no idea what version I was running before.

I'm using Windows 7 on a Dell Inspiron 1525 laptop.

I appreciate that this is all very vague and there's probably not an answer out there, but I thought I'd speak up in case others are dealing with similar things.

Kind Regards,
Wendy