Windows 10 Folder Icon color

[maestro]

The folder icons that were yellow are now white on my hard drive. They are yellow when viewing the contents of a USB drive.
How do I get the yellow ones back??

 

[Neemobeer]

Open a Powershell prompt and run the following two commands. This should reset the thumbnail cache.

gi $env:LOCALAPPDATA\Microsoft\Windows\Explorer\thumbcache* | Remove-Item
Stop-Process -Name explorer