had the same thing happen to me. I want to make sure my iphone is clean, not sure if the restore of my 1.4 back up on to the 2.0 firmware has any thing else in it that could screw up so I erased all settings and media using the settings app on the phone. Then hooked it up to itunes and said it was new new phone. Gave my phone a new new name and synced all contacts and book marks back. Then I just recreated my mail accounts on the phone did a resunc with iTunes, which made a back up. Now every thing is running great just waiting for 2.0 jail break to get my nice apps back

Same story here, mail crashing till I setup without restoring.

Originally Posted by jds17j

ok, i figured out how to update and use my backup to restore... my mail.app works now without problems! Anyways, here is what to do:

1. Restore with 2.0
2. When you get to the screen in iTunes where it asks if you want to restore a backup or start over new, unplug the iPhone.
3. Open Mail.app on the iPhone and add an email account.
4. Replug iPhone and restore your backup.
5. You should now be able to open up mail and add/delete old accounts, etc...

This worked! Let me add that you don't need to unplug the iPhone in the middle.