How to Fix: MS Office Key Not Valid, Won't Activate

Dennis Faas's picture

Infopackets Reader Pat P. writes:

" Dear Dennis,

I recently had to rollback Windows 7 because the system appeared to be corrupt. The rollback worked. However, now whenever I try to open MS Office it starts up with a message that it is configuring MS Office, then says 'MS Office requires validation'. I chose the option to activate on line (or by phone), but then all I get after that is a message that MS Office could not be activated because the product key is invalid. What do I do now? "

My response:

I did have this exact same problem a few months back with another user. The scenario was almost identical. The reason you're receiving this error message is because a configuration file or part of the MS Office binaries are corrupt / out of sync which is most likely the result of the rollback.

From what I read online there are two ways that you can go about fixing this issue, though the third method (which I will also describe below) is the one that fixed it for me.

Option #1: Repair MS Office using Control Panel

The easiest way to fix this problem is to repair MS Office. You can do this by doing the following:

  1. Click Start, then click on Control Panel.
  2. Double click Programs and Features (or Add / Remove Programs), then locate MS Office in the list. Once you find it, double click it.
  3. The MS Office installation wizard should now appear. Choose the option to Repair MS Office.
  4. Once the wizard completes, try and run MS Office again and activate it like you normally would.

If that doesn't work, proceed to Option #2.

Option #2: Reinstall MS Office

If the repair didn't work for you, then another way you can try and fix this problem is to uninstall MS Office and reinstall it. Note: if you use Microsoft Outlook, your data files (emails) will remain untouched as they are part of your user account. If you reinstall Outlook it should find the files again without any issues. To uninstall and reinstall MS Office, do the following:

  1. Click Start, then click on Control Panel.
  2. Double click Programs and Features (or Add / Remove Programs), then locate MS Office in the list.
  3. Left click MS Office to highlight it, then right click over top of the highlighted line and select "Uninstall".
  4. MS Office should now uninstall. If you receive an error message that it could not uninstall, then simply reinstall MS Office as described in Step #5. This will effectively reinstall MS Office over top of itself; most of the time this will fix any corruption as a result of attempting to uninstall - and hopefully even fix MS Office itself.
  5. To reinstall MS Office, locate the MS Office disc (if you have one) and insert it into the machine, then run the Setup.exe file. If you don't have a disc, you should be able to download various versions of MS Office online - search Google for the download link. Example "download ms office 2013" would likely bring up a page to download MS Office 2013 from Microsoft.
  6. Once MS Office has finished installing, try activating it.

If it still doesn't work after this point, proceed to Option #3.

Option #3: Backup, Format, and Reinstall Windows

Unfortunately a repair and even a reinstall doesn't always fix MS Office. In this case, it's usually because Windows is corrupt (here's a link explaining why) and is causing you grief. The easiest way to get past this hurdle is to backup your entire computer (a disk image is recommended), then format the hard drive, reinstall Windows, all your programs, and MS Office. At this point it should work.

This is the method I had to use to fix MS Office for one of my clients using remote desktop support, because we simply had no other choice in the matter. If Windows is corrupt, it will behave erratic and will prevent you from doing things - such as installing some programs. It is a big step to take, but in the end everything worked the way it should, including MS Office.

I hope that helps.

Additional 1-on-1 Help: From Dennis

contact me briefly describing your situation and I'll get back to you as soon as I can. For what it's worth, this is also a great opportunity to streamline Windows because a clean install means there won't be any junk slowing down your PC - it will be like it was brand new again.

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I need more computer questions. If you have a computer question - or even a computer problem that needs fixing - please email me with your question so that I can write more articles like this one. I can't promise I'll respond to all the messages I receive (depending on the volume), but I'll do my best.

About the author: Dennis Faas is the owner and operator of With over 30 years of computing experience, Dennis' areas of expertise are a broad range and include PC hardware, Microsoft Windows, Linux, network administration, and virtualization. Dennis holds a Bachelors degree in Computer Science (1999) and has authored 6 books on the topics of MS Windows and PC Security. If you like the advice you received on this page, please up-vote / Like this page and share it with friends. For technical support inquiries, Dennis can be reached via Live chat online this site using the Zopim Chat service (currently located at the bottom left of the screen); optionally, you can contact Dennis through the website contact form.

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