Close all Adobe apps :
1) Right click on Finder icon and select "Go-To" Folder option.
2) You will get a text box, type-in below command and then hit 'Return' key.( " Do not miss ~ symbol " )
It will open User Library folder.
3)Then navigate to Application Support>Adobe>AAMUpdater.
Open AAMUpdater folder and rename 1.0 folder to Old-1.0 .
Then launch Photoshop cc app and click on Help menu and select Updates option and check.
Now I'm getting download error (49). Disabling virus scanning didn't help.
Thanks for the answer though - at least I'm getting different errors now
Sign out from Adobe Creative Cloud .
Force Quit all Adobe related processes like Creative Cloud, CoreSync, AAMUpdater....etc from Activity Monitor .
[ Applications > Utilities > Activity Monitor ]
Then relaunch Adobe Creative Cloud app and try to update.