Mail gone, wont quit or display anything after update...

Question

Hi Folks,
In the process of helping my dad upgrade his G4 mini to 10.5.6 from 10.4.something. He's on dialup still so screen sharing to get him going is not really an option and I"m trying to help him with this over the phone and it's slow going. The upgrade DVD ran fine and there were no problems that he noted. The machine is now running 10.5.6 that came on the DVD all OK. It is able to go online and safari works. Mail however has choked.
THe window opens when you run the program, but no mail is displayed when you select inbox or any other mailbox. The right hand pane of emails is blank. He is able to select to write an email and has sent several to me but they were never actually sent, nor do they show in the drafts or send email or any other email box. I have attempted to rebuild the mailboxes from the mailbox menu, and while it allows him to select this it doesn't help, still no messages displayed.
Further, Mail wont quit. When you try to quit it it hangs and it requires that you force quit it before you can restart the machine.
All the account preferences and passwords and addresses appear to still be there, you can go to preferences and see the settings. This is a POP account not an imap account, so there should be local copies of all the messages he has received and kept in his inbox.
I suspect a database issue or something? Is there a way to totally rebuild the database from scratch?
I did try running the vacuum index command from the terminal and that ran without returning any errors, but did not fix the problem.
Any suggestions greatly appreciated thank you!

Answer 1

I found it! Here is the answer from "troubleshooting".
Resolution
Force quit Mail if necessary: From the Apple menu, choose Force Quit, select Mail in the Force Quit window's list of applications, then click "Force Quit".
If the issue persists after relaunching Mail, follow these steps while Mail is not running:
From the Finder's Go menu choose Go to Folder.
Go to this location (type or paste the tollowing, then click Go):
~/Library/Mail
Move the items named "MessageRules.plist" and "MessageRules.plist.backup" to another location, such as your desktop.
Note: If you previously upgraded from Mac OS X 10.3 to Mac OS X 10.5, the files will be named "MessageSorting.plist" and "MessageSorting.plist.backup".
Open Mail. Note: At this point you can either set your Junk Mail settings and re-create your Mail rules manually in Mail preferences, or follow the next two steps (if you re-create rules and Junk settings, do not perform the following steps).
Quit Mail.
Place the items named "MessageRules.plist" and "MessageRules.plist.backup" back in the ~/Library/Mail folder (replace any copies that were added to ~/Library/Mail when you opened Mail).