So if you have a mac, and want to install a texture pack, let me show you. This will also solve, the grey icon error!

1) First download a texture pack using FIREFOX. DO NOT USE SAFARI. That is what is causing the grey icons!

2) Navigate to your minecraft folder by opening finder, and at the top click the GO tab, then at the same time hold down the option/alt key. That will make a tab called library appear. Click on that, then go to application support. Your minecraft folder is in there somewhere!

3) Inside your minecraft folder is a folder called 'texture packs'. Open that :)

4) In another finder window go to download in the left bar. Find the texture pack you downloaded. Drag that into the texture pack folder. It should be a .zip file, or looks like this:



5) Open minecraft and click on the texture packs tab, from the menu!

YOUR DONE!!! Hopefully that fixed the grey icon!

HOW TO FIX A GREY TEXTURE PACK:
There are a few things that cause this like mcpatcher not being installed, but MOST COMMONLY...

USE FIREFOX. DO NOT USE SAFARI. IDK WHY. IT JUST WORKS.

PLEASE GIVE ME A DIAMOND IF THIS WORKED! IT WILL HELP OTHER PEOPLE TOO!