Most program icons look the same after high sierra update After an update to high sierra most program icons look the same.



Any ideas how to fix that?
Do you have League of Legends installed on your Mac ?
It seems to be the cause of the issue for many other mac players.

https://boards.na.leagueoflegends.com/en/c/bug-report/rA0p1rYx-client-updating-on-mac-high-sierra-messes-up-other-application-icons

Unfortunately there is nothing you can do until Riot acknowledged the problem and deploy a fix.