MacOS Sierra Missing App Icon in Dock and “Check for Updates…” Fails for Certain Apps

macos

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?

Best Answer

Specifically regarding the warning you are seeing, from Rogue Amoeba:

Gatekeeper Path Randomization ... works by mounting a read-only disk image in a temporary path in the file system, copying the app onto that disk image, then launching the app from there.

GPR is a new security feature in Sierra intended to close a loophole where malicious programs could be packaged with Developed ID-signed legitimate programs, and thereby bypass Gatekeeper security intended to prevent unsigned applications from running.

GPR is disabled after an application is moved to the /Applications folder, however software update systems will fail, because when the new version of the app is downloaded, it has to be moved by the user before it will execute outside of the read-only disk image imposed by GPR. Therefore the best way to update is to download an updated copy of the app from the developer's website and manually move it to the /Applications folder.

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