You ran the script, set the value, even restarted - and the Snipping Tool opens like nothing happened. Do not reinstall Windows and do not start deleting keys at random. This failure has a short list of causes, and nearly all of them are placement mistakes: the right value in the wrong key, the wrong hive, or something quietly writing it back.
A policy that "does not work" is almost never a broken Windows - it is a detail. The DisableSnippingTool value only counts when it sits in the exact policy location, with the exact name, as the right type, for the account you are testing, in a session that has actually reloaded policy. Work the six checks below in order and change one thing at a time; the cause usually shows itself by check three.
Similar-looking TabletPC keys exist elsewhere in the registry and do nothing as policy. Location, spelling and type all have to be right at once.
The registry contains more than one key with a similar name, and only one of them is read as policy: HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\TabletPC. If your value sits under a TabletPC key anywhere else - left there by a guide that printed a shortened path, or by your own navigation slip - Windows politely ignores it forever. Open Registry Editor and read the full path in the address bar, not just the last folder name.
The value must be named DisableSnippingTool, be of type REG_DWORD (32-bit), and hold data 1. Windows fails silently on every variation: a typo in the name, a text (String) value instead of a DWORD, or data left at 0 all produce exactly the symptom you have - nothing happens, with no error anywhere. Delete the wrong value and recreate it cleanly rather than editing a doubtful one.
The same value exists in two policy hives and they cover different people. Under HKEY_CURRENT_USER it applies only to the account that was signed in when it was set. If you set it as the admin, signed in as a staff user and watched the tool open, the block may be working perfectly - for the wrong account. For the whole machine, the value belongs under HKEY_LOCAL_MACHINE.
Policy is read at sign-in and at refresh intervals, not continuously. If you edited the registry and tested ten seconds later in the same session, you may simply be early. Sign out and back in - or restart - and test again. When Group Policy delivered the setting, gpupdate /force in a terminal forces the refresh immediately. Only keep digging after a fresh session still opens the tool.
If the block works, then quietly stops working after restarts or overnight, something with more authority is managing that value: a domain GPO, a logon script, an RMM agent, or a tuning tool that "restores" settings. Find the owner instead of fighting it:
gpresult /rLook closely at what actually appears. Xbox Game Bar (Win + G) captures screenshots and recordings, and third-party tools like ShareX, Greenshot or Lightshot draw a selection box that looks very much like a snip. If one of those is what "still opens", your policy is fine and was never aimed at them. Two related settings are worth reviewing while you are here: in Settings > Accessibility > Keyboard, Windows 11 can open the snipping interface from the Print Screen key - and remember that Print Screen itself copies the screen to the clipboard whether or not any tool opens.
Watch the working version in the video - the tool refusing to open is what success looks like.
▶️ Watch Full VideoYou probably set it under HKEY_CURRENT_USER, which covers only your account. Set the same value under HKEY_LOCAL_MACHINE to cover every user on the PC.
Usually a policy refresh, a management tool, or a cleaner utility changed the value back. Run gpresult /r to see which policies apply, and check whether the value is still present in the TabletPC policy key.
Some cleaner and tuning tools do flag policy values they do not recognise. If the value keeps disappearing on a home PC, check that tool's ignore or restore settings and whitelist the TabletPC policy key.