This is a known error on macOS. This error occurs should you have installed the new operating system Mojave on your Mac. In order to once again display the icon and status of your folders, please follow these steps:
Open System Preferences, click Extensions, and then click Finder Extensions. Now select 'DesktopClient Finder Extension'.
If this does not solve the problem, follow these steps:
- Press and hold alt/option on your keyboard.
- Right click on theFinder icon in your Dock.
- Click on “Relaunch”.
- Open the Finder.
- Click on the Apple symbol located in the menu at the top of your screen and hold (Shift) on your keyboard.
- Click on “Force Quit Finder”.
- Open the Terminal.
- Type “killallFinder”.
Your Finder will restart and the icons as well as the status of your folders should once again be visible.