If your OneDrive for Business sync stopped working after you installed Skype for Business, this could be due to a corruption of your Office cache.
Why does this happen? Basically, there are two installation types and they don’t work together, as described in this article:
Side-by-side installations of MSI and Click-to-Run versions of Office 2013 are not supported: https://support.microsoft.com/en-us/kb/2753630
How to fix it
If you have mixed install types, you need to decide which one you want to use, remove the other install type, and then reinstall the other Office applications as the same type. To ensure that you have completely removed one install type, it is best to uninstall all Office packages, and then reinstall everything with your chosen install type.
There is a public Fix It tool in the following article that will uninstall all Office packages for you. This tool uninstalls all Click-to-Run components on the first run and all MSI components on the second run.
To reinstall Office and Skype for Business with MSI, you need to install Office 2013 Pro Plus from the original source, or install Office 2013 Standard from the original source, and then download and install the MSI standalone version of Skype for Business.
To reinstall Office and Skype for Business with Click-to-Run, use the O365 Portal https://support.office.com/en-us/article/Download-and-install-Office-using-Office-365-for-business-on-your-PC-or-Mac-72977511-dfd1-4d8b-856f-405cfb76839c.
NOTE: We have introduced a check for this incompatibility to prevent this issue for new installations. For details, see: https://support.office.com/en-US/article/Office-installed-using-Click-to-Run-and-Window-Installer-on-same-computer-isn-t-supported-30775ef4-fa77-4f47-98fb-c5826a6926cd
Written by: David Wells