Welll here is an update for those who get an Exception screen. I went to the genius bar and they immediately indicated it was a hard drive failure. All they do is hardware replacements anyways. OK so I went home and did some poking around through my eDrive partition. Seems that Mountain Lion modified all my permissions. To be sure that I didn't have any bad sectors, I did a complete test of my HD. Everything was fine except the permissions.
So I proceed to do a restore back to 7.3. I am up and running fine. Some lose of applications and files I had not backed up since April.
To Apple..... What would you recommend as my next step! I have 2 users created on my system plus a Fusion partition. I have paid for an upgrade that does not function.
Finally have it solved.
1. I backed up to 10.7.3 (only backup I had.
2. Did a scan of my hard drive Surface and also Permissions. All good.
3. Installed 10.7.4
4. Did a scan of my hard drive this time only Permissions. This time I had permission errors croppig up. Repaired them and restarted my laptop.
5. Rescanned my hard drive for permissions all good.
6. Backed up this hard drive image.
7. Installed Mountain Lion from my backup hard drive. I had saved a copy last time:-)
8. After installation this time it worked!!
I got this idea yesterday sitting next to a guy at the Genius Bar who had issues with his laptop after upgrading to 7.4. Note, permission errors must have been there all alomg but never caused an issue for months. This upgrade was not forgiving.
Hope this helps some one else. After 4 attempts of installing it finally worked.