Why can't I change Window 10 registry key?

Solution 1:

Interesting. I'm on Windows 10 Pro x64 and I can edit the value.

Right click on Advanced and choose "Permissions".

Click your user name and make sure you have full permissions:

If you don't, try allowing yourself full control (if the boxes are available).

If they're greyed out like in my screenshot, but you don't have full access, you can try to take ownership of the object by clicking Advanced

Then next to Owner click Change:

Type your username into the box and then press Check Names. Press Okay, then before you press Okay again make sure the following is selected: