Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
My 'mach_kernel' is visible and I had no problems updating Microsoft Office. Just because it's visible does not cause the problem. This suggests other issues with the update. As users have reported here re-installing Mountain Lion fixed the problem for them.
OS X 10.9 (Mavericks) is due out this week hopefully up-graders will see this problems resolved by the new OS X.