Q. My event viewer shows – 

Installation Failure: Windows failed to install the following update with error 0xC1900208: Upgrade to Windows 10 Pro.

Looked up error and it says that there is an incompatible app??? So do I start uninstalling my apps and programs one at a time until the install works? HP Pavilion laptop, AMD-A6; 6GB memory, Windows 8.1

Answer.

I took a different approach on this problem since I could not identify a particular App or program that was causing the problem.  I thought that perhaps the WIN10 download itself was the problem. I went searching and came across this — http://answers.microsoft.com/en-us/windows/forum/windows_10-update/how-can-i-fix-windows-update-error-cumulative/c4372ddc-224c-46dd-856c-53b128b26a6b?auth=1  

I used the method 2 – stopping the update services, renaming the download folder, and restarting the update services.  It took a while to re download, but then I could complete the WIN10 install successfully.  I still have some other problems, but this did fix the update problem.