Repeated crashes in Contacts, Bento, Mail in OS X 10.8

Question

I was having problems with Contacts, Bento, and Mail crashing frequently since installing 10.8. Apple Support suggested disk repair, resetting PRAM, and reinstalling OS X 10.8, none of which fixed the crashes. About the same time that I upgraded to 10.8, I joined an organization that uses an Exchange server, and the IT guys added an exchange account to Mail, which automatically linked to Contacts and on through to Bento. I noticed today that there was something wrong with the way the Exchange server account was set up, and my MacBook Pro was not connecting to the server properly. As soon as I turned off the Exchange account in Mail and Contacts, crashing in those apps and in Bento appeared to cease.
So, check to see if you have a bad account in Mail or Contacts. If you do, try turning it off and see what happens.
I'll add an additional post if this changes.

Answer 1

Please follow these directions to delete the Mail "sandbox" folder.
Back up all data.
Triple-click the line below on this page to select it:
~/Library/Containers/com.apple.mail
Right-click or control-click the highlighted line and select
Services ▹ Reveal
from the contextual menu.* A Finder window should open with a folder named "com.apple.mail" selected. If it does, move the selected folder — not just its contents — to the Desktop. Leave the Finder window open for now.
Log out and log back in. Launch Mail and test. If the problem is resolved, you may have to recreate some of your Mail settings. You can then delete the folder you moved and close the Finder window. If you still have the problem, quit Mail again and put the folder back where it was, overwriting the one that may have been created in its place. Post your results.
Caution: If you change any of the contents of the sandbox, but leave the folder itself in place, Mail may crash or not launch at all. Deleting the whole sandbox will cause it to be rebuilt automatically.
*If you don't see the contextual menu item, copy the selected text to the Clipboard (command-C). In the Finder, select
Go ▹ Go to Folder...
from the menu bar, paste into the box that opens (command-V). You won't see what you pasted because a line break is included. Press return.