An error was viewed in SIM soon after upgrading. Error was in the InstallLog\Altiris_ns_8xxx_x64.msi_install.log.
Error: Platform Core -- Error 1310. Error attempting to create the destination file: D:\Program Files\Altiris\Notification Server\RootWeb\Images\a3.gif. System error code: 0
Trying to view this Folder resulted in the following message:
For this issue, SIM didn't give a very good indication of what was failing. The Install Logs were terrific though and pointed directly to the issue. Logs are found here:
C:\ProgramData\Symantec\SMP\Logs\InstallLogs
The resolution to this issue was to rename / delete the Images folder, and recreate a new folder named Images. Then try the upgrade again.