I was having the same problem for the latest CC (as of 12/19/16). None of the fixes that I found in the forums were working. I contacted support through "chat" and they solved the problem. As one might suspect, some of the license files get out-of-date or corrupted. This is the set of steps and files to delete that worked for me. I am running Windows 10. I just removed my "done" comments. At the end, I signed in again and all was good. Hope this helps.
Abhishek: Hello! Welcome to Adobe support.
Abhishek: For now, sign out from Creative Cloud Application, You will get that option on Gear icon> Preferences > Sign out.
Abhishek: Now choose QUIT.
Abhishek: Then open Task Manager by pressing ctrl+shift+ esc
Abhishek: From processes tab, end creative cloud.exe process.
Abhishek: You need to close all Adobe related processes:
Abhishek: AAMupdater, AdobeUpdateService, AAMupdater notifier, Adobe GC client Application
Abhishek: Adobe Crash demon, Coresync, CCLibrary, CCXprocesses, adobedesktop service
Abhishek: Now press Windows key and R together from your keyboard and paste the following:
Abhishek: %localappdata%
Abhishek: Under that Adobe folder, delete OOBE and AAMUpdater folders.
Abhishek: Again press Windows key and R
Abhishek: %programdata%
Abhishek: Then navigate to following: Adobe < SLStore folder
Abhishek: Delete all the contents of SLStore folder ( Hidden files as well )
Abhishek: Again press Windows key and R
Abhishek: C:\Program Files (x86)\Common Files\Adobe\SLCache
Abhishek: Delete all the contents of SLCache folder as well.
Abhishek: Now try opening any installed CC product.