I'm just throwing a few ideas in here because there's not much info there and nobody else has responded yet.

"Just about any message" - so not ALL messages then? Can you identify any common features between messages in the two groups (HTML/rich text messages, attachments, size, sender...)?

Alternatively, will it crash on any message given the right circumstances (second message opened in the session, preview mode switched on...)?

Have you checked for disk errors? Perhaps there's a bad sector and corrupted files.

Hello,

I just updated from Pmail 4.3 to to 4.51. After I open just about any email message, PMail suddenly closes.

Any ideas why?

Thanks.

 Shmuel