I spent 3 hours with Avast support today and they had to admit there is a problem. The Avast "Web Shield" blocks connectivity between the Adobe Cloud and Photoshop. My PS won't even launch - it hangs up at syncing preferences - unless I turn off the Avast Web Shield.
While using PS, I get additional syncing errors unless the Web Shield is off. Shutting down the Avast shields, of course, leaves my PC vulnerable.
(As a side note, the Avast Mail Shield blocks all incoming and outgoing mail in Outlook 2010 which is my mail program of choice. It also blocks all activity using Mail Washer Pro (spam filter).
If you are a heavy Photoshop user as I am (and have been for 30 years), I strongly suggest NOT to use Avast