Step 3: I have mentioned the “ Personalize” folder that is not in the Themes folder. Step 2: You have to reach “ HKEY_LOCAL_MACHINE\SOFTWARE\MicrosoftWindows\CurrentVersion\Themes\Personalize,” which is a little bit of work, but you can do it. Step 1: In the Cortana, or search bar, type “ Regedit.” But, you have to enable the dark designs manually using a few commands and let me guide you through it. The Windows 10 official dark theme does not have a specific tutorial, and it does not slow down your PC, and it makes the perfect dark theme. We know the impression you have on your face that every tutorial on the topic suggests you the official version of the dark theme in Win10, right?