application icons changed after upgrade to high sierra

Launch Terminal Triple click anywhere on the following line to copy entire line then at the prompt copy & paste this command: Then press return. Wait for the cursor to return to the command line.

Open the Finder. From the Finder menu bar click Go > Go to Folder

Type or copy paste the following:

~/Library/Caches/com.apple.finder/Cache.db

Click Go then move the Cache.db file to the Trash.

Restart your Mac.

* Credit to Carolyn Samit for this.

I found another method posted by Embraer190driver that worked for me, see below:

Restart, press and hold Shift key when the start up tone is heard. The goal is to start up the computer in Safe Mode (as indicated in top right hand corner of mac). IF icons appear as they should while in safe mode, go ahead and restart computer again normally.

All the icons are now back.

If it's only wrong in the Dock, you can try removing it from the Dock, then dragging it down from her Applications folder to the Dock, to create a fresh alias.

Sounds like the icons have become the generic icon for applications. Is this happening only in your Dock or in the Applications folder as well?

Glad you got it sorted. Safe Mode cleans some cache files on startup, so that must have done it.

Right, that one was a corrupt cache file, mentioned in an earlier reply. The Dock icons being generic can be due to various factors.

I have just tried this and it doesn't make any difference, the generic icons are still there in Dock and in Finder. Is there something else that can be done to correct the problem? One thing I have noticed is that in preview window in Finder and at the top of Get Info windows the icon appears correct.

Terminal is in Applications > Utilities. It is a command line application.

Or, just type Terminal into Spotlight search.