Help, icons turning to pen and paper!

[Sun Salute]

Look at the far right icon in the dock - it's my system preferences open. Why does it look like pen and paper? And the same thing is happening in the application folder - half of the icons there (quicktime player, mission control, siri, screenflow) and so on suddenly turned into this weird symbol. How do I get rid of this?

 

[dianeoforegon]

Try restarting in Safe Mode.
1. Start or restart your Mac.
2. Immediately after you hear the startup sound, press and hold the Shift key.
3. Release the Shift key when you see the Apple logo appear on the screen.

If that fails, try try OnyX https://www.titanium-software.fr/en/onyx.html

Once you launch OnyX, you’ll find LaunchServices listed in Maintenance > Rebuild. Just check the LaunchServices box and press Execute to rebuild it.

Onyx has some powerful features. Use with care.

 

[Allyance]

? I can't see what the OP is talking about. Icons look normal to me. Last icon is Trash Can, then his desktop showing through.

Ok, I see it now, look like the letter A on my screen. Since icons are separate little graphics files, looks like it is corrupt.

 

[T'hain Esh Kelch]

That is the standard icon for applications that don't have one. My guess is you have some permissions problem. You could try to reinstall the latest combo update, and see if that fixes things.

 

[DeltaMac]

? I can't see what the OP is talking about. Icons look normal to me. Last icon is Trash Can, then his desktop showing through.

OP is referring to the last app icon, which is actually the third from the right end of his dock.
OP claims it is the System Preferences, so the icon for that has reverted to a generic icon.
The OnyX rebuild tip will likely fix this.