macOS Sierra Missing App Icon in Dock and "Check for Updates..." Fails for Certain Apps After doing a clean install of macOS Sierra I occasionally get the 'missing app icon' (the original app icon with a question mark superimposed). When this happens clicking the app icon doesn't launch the app (and I need to go to /Applications and re-drag the icon to the dock). Anyone else experiencing this issue? 

I also get the following warning for the apps this is happening with when trying to do an update:


  Sketch can't be updated when it is running from a read-only volume like disk image or an optical drive. Move Sketch to your Applications folder, relaunch it from there, and try again.


I've tried opening from the command line to verify I am indeed opening from the Applications folder with:

open /Applications/Sketch.app


Any thoughts?
Cause: Gatekeeper Path Randomization introduced by macOS Sierra.

Steps to Fix:


Run command: xattr -dr com.apple.quarantine /Applications/Your.app
Drag app back to Dock;
Restart Mac.


Consequence:


App icon stays at Dock after restart
Check for updates works