Does Lightroom load? Are you using the same catalog? Are you running in administrator mode or using an administrator account, or are you using a user account? If your catalog located in the same folder it was in prior to the Windows 10 upgrade? If Lightroom will load, what do you see? Are there any error messages?
I run Lightroom CC 2015 using my administrator account. I don't have a user account. After Windows was upgraded I had no problems.
I am using the stand alone cd-version (not the cloud version)..LR does load the catalog, the raw files are in the catalog, the names of the files are correct and even the stars are there, but no thumbnails..i run it as administrator..and there are no messages..
Thanks Jim, in the meantime i found out that the solution is descibed in the following link:
Thanks a lot for helping me.