My Win 7 was an upgrade from Win XP, and all emails were imported from Outlook Express. Everything works OK except that T'bird is pathologically slow with any emails that involve attachements. They are slow to send, or download; slow to delete; and slow to move from one folder to another. By "slow", I mean minutes, not seconds. When downloading emails with images attached, for example, Thunderbird will appear to hang, and the header will show that T'Bird is "not responding", but it's simply working like a old snail in the background. Really, the wait is intolerable, and makes T'Bird unpleasant to use. Outlook Express had no such problem. If no attachments are involved, T'Bird works OK. I use Win 7 Home premium 32-bit; I use Windows Defender but no other Anti-Virus (because I know that they can be responsible for slowing operations such as this); Win 7 disk indexing is "off"; and I am currently using T-Bird 60 (but wondering whether a much older version would be better for Win 7). I've searched long and hard for a solution to this, using Google, but haven't found a solution. Your help in finding one would be much appreciated.