If it's slow or you're having some other issue
If you’re having problems with any Office program like Word, Excel or Outlook, you can always perform a repair, which will try to fix any issues that may be causing the program to not load properly or some other type of problem.
Repair MS Office
To repair Office, you first have to open the Control Panel and then click on Programs and Features.
Click on the Office version you have installed and then click on the Change button.
Next, click on the Repair radio button and click Next. This will start the repair process.
In Office 2016, the first screen that appears when you click Change is the repair Office dialog. Here you have the option to try a quick repair or an online repair. The online repair is handy because it will download all the latest fixes to solve the problem.
It’ll take some time to repair and once it has finished, you’ll see a message saying the configuration of Office 2013 is complete. You’ll then have to restart the computer in order for the repair to complete.
Repair is a great Office tool that I have used in many previous versions of Office to fix things like the Normal.dot template being changed in Word, Outlook PST and email problems, etc. If Office is running slow or having some other issue, try performing a repair and hopefully it will fix your problem. Enjoy!