I was away for six weeks using a different computer, and when I got back to my home Windows 10 machine I tried to update my Adobe apps. For the last few hours Creative Cloud has been stuck at 9% and all other apps say "Waiting...":
Make sure that you have all Windows updates that are available.
The one thing that was causing it for me, believe it or not, was that I needed to do a clean installation of the latest Studio graphics driver from the NVIDIA website. After doing that and restarting, all was OK.