Vista Home Premium.
Apparently this problem is documented back to 2007, but getting ridiculous now. I don't remember the date of the Window Update, but after one of them Thunderbird email client began to slow when sending any emails. It is now at the point where about 10% of the emails I send will Time-Out and the others take a brutally long time for the mail to be delivered. Makes no difference if it's a one word email or large one with an attachment.
I routinely compact the TBird folders, I tried deleting the .msf files and restarting, clearing cache, etc.
BTW, I tried getting answers via Mozillazine but the responses have not helped in the slightest and generally very uninformative.
Any help would be greatly appreciated.