Coresync process not closing at shutdown

first, see if you can update your cc app.

if that fails try resetting the cc app: To reset the Creative Cloud desktop app, make sure it's in the foreground, then press:

Win: Ctrl + Alt + R
Mac: Cmd + Opt + R

if that fails, turn off file sync'g to see if that solves the problem.  if it does, you have some file(s) that not able to sync.