Installation Failing To Start


I've already removed my previous version of Office and each time I attempt installing Microsoft 365 I get the following error message:

Couldn't start Office installation

We're sorry, but we could not start your Office installation. Another installation is in progress. Please try again later.


  1. Download the Fix It application.
  2. Run the Fix It application titled O15CTRRemove.diagcab.
  3. Select Next.
  4. It will take a couple of minutes before the Fix It application finishes removing all traces of previous Office installations.
  5. Select Finish.
  6. Restart computer.
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Article ID: 1300
Fri 4/3/15 1:15 PM
Thu 9/14/23 11:19 AM

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Information for Faculty/Staff/Students about installing Microsoft 365 on a personal computer.