I had the same problem. I opened of the activity monitor and found the Creative Cloud process and killed/quite the process then I opened the applications folder and relaunched The Adobe Creative Cloud app. Hope this works for you.
Please try the Following Steps:
For MAC OS
Open Activity Monitor
>Look For Adobe Processes
>Force Quit Creative Cloud
>Force Quit Core Sync
>Force Quit Processes Related to Adobe.
Try Launching Creative Cloud Desktop again.
If you Still get the spinning circle Repeat the above Steps, You will get the Login screen and it will start working.
This worked for me.
These steps didn't work for me.