Change icons in Mac OS?

If you see Lanny's post, you can actually see a tint of green on the top of the Apple TV icon - that might be more re-enforced on your macs display depending on the calibration profile. That green thing is supposed to make it look 3D-ish. It's actually grey but to some it may seem green. (to me it seems a bit greenish - not too much)

You probably have two problems:

1. Make sure SIP is disabled
2. Make sure you don't have a random png file you got from Google. It has to be AppIcon.icns with 4 or some different icons in it.

If none of that works, clear your cache.

Right click Finder, click Go To Folder, and type in the following without the quotes:

"/Library/Caches/"

Delete the folder which says something like: "com.apple.iconservices.store" To make sure everything is gone, you can delete everything in the Caches folder.

To be even more sure, go to "~/Library/Caches/" (without quotes) to go to the user caches folder. I'm not sure deleting everything in this folder may help, but you can select everything in there and get rid of it. You also might free up about 500MB.

Note that this method MAY affect other apps.

Then restart the computer - or better still, shut it down, wait for a minute or two, and start it up again.

Yes, it just may be a bit harder - you might have to dig Google a bit more to find out.

I'm not exactly sure how macOS Big Sur's new security feature works, but if you're expert at the terminal, you can make a bootable macOS usb and change the files via command line. However, it may be detected somehow and may result in a system failure.

I suppose all this trouble is unnecessary for just a change of an icon.

No, I am not saying that it is possible to make changes to Apple's System Icons in Big Sur. As of Apple's background security updates on November 13, 2020, it would appear that anything that is an Apple App or System File, belongs to the System, meaning Apple. If you were to "Get Info" on any Apple App, you may see that your Apple ID/Admin name is no longer there, it may say, "System." If you do try to add "Administrators" to the accessible list, you may or may not be successful. You will know if you are not successful, if you see a message that pops down, telling you that you do not have the proper permissions to make that change. That is what has happened to my computer, and I have not even done the update to Big Sur!

You may also "Get Info" on a third-party App, and see the same things that I have mentioned. You are more than likely to be able to add "Administrators" to those Apps. I did, for the most part.

I am just trying to keep it together and my head from exploding.