[Back up 15 and punt]

I am using mail under 10.5 and I have been having problems quitting this application. The only way to quit is to use "force quit". Has anybody else experienced this problem and has anybody found a solution?

[Andy8]

I am having the exact same problem on my old PPC G4 Powerbook running 10.5, but on my new MBA its not an issue.

[mduell]

I have the same issue on my MBA.

[zombie punk]

It's so common I'm pretty sure it's a bug in mail to do with trying to quit while it is trying to download mail.

[Cold Warrior]

I don't remember if Mail has this option, but it could be set to delete messages on Quit. This is a feature of some mail clients with IMAP. If so, disable that option and see if it helps.