Let's say the key is HKEY_CLASSES_ROOT\Folder\shell, enter image description here

and i edit the value to empty

enter image description here

Then how can this registry key reset back to (value not set) state ? I tried reg add HKCR\Folder\Shell /t REG_SZ /f(without /d) but no luck.

  • 2
    What's the significance of this "value not set"? Why is it important for you to have that state? From a functional viewpoint, they're the same
    – Dr.Ping
    Dec 24, 2015 at 19:07
  • 4
    None and empty string is different in programming viewpoint, and i'm not registry expert to know t is there any side effect to left it empty. The quickest and safest way is reset to how its original look like.
    – 林果皞
    Dec 24, 2015 at 21:38
  • 1
    I'm not a programmer either. Unless you know that there is a functional difference, I'd assume that there is no difference. They're both Null.
    – Dr.Ping
    Dec 24, 2015 at 21:41
  • 3
    I don't know "functional difference" or not, that's why i ask. Windows is closed source, how you know the hidden functionality powered by hidden source code ? What if this empty string for this particular registry key will crash one app in future ? Null and empty string is difference stuff in coding.
    – 林果皞
    Dec 24, 2015 at 22:26

1 Answer 1


Just delete it. The default stays there with (value not set)

  • 2
    Is there a method without 'deleting' it?... as that's not a trivial method if there are many peer values & subkeys (& yes, I know you can export the key, delete it, then re-add it with the changes/deletions made; but I'm hoping there's a more elegant approach. Apr 20, 2020 at 13:58
  • 1
    Delete the STRING (default), not the KEY it's in. Aug 9, 2023 at 0:04

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