Yesterday, Microsoft announced the Office 2016 Public Preview, a product version available to the general audience. Office 2016 is the successor of Office 2013.
I installed Office 2016 Public Preview on my existing machine that already had Office 2013. Both Office versions work just fine.
But then, I decided to remove it. After I removed Office 2016 Public Preview, my Office 2013 stopped working.
I began getting this option on the Info page and error messages when I tried to open my emails.
How to fix it?
A repair will fix it. To repair, go to Control Panel, select Microsoft Office Professional Plus 2013 (or the version of Office 2013 you have installed), right-click on it and select the "Change" menu item.
On the next screen, select the Repair option and let it go.
In the end, you will need to reboot your machine and you are good to go.