I believe you are referring to the blank white window of CC desktop app.
Please refer to the threads below where this issue has been addressed:
Thanks Sheena - you did the trick - have a great weekend
You are welcome Ned!
You too have a great weekend.
P.S. when using the adobe forums, please mark helpful/correct responses of Staff or helper, if there are any.
The ones I am reading all seem to be for Windows. What about us Mac users? Is Adobe developing a patch to repair this issue or do I need to spend another day trying to repair?