Sometimes when you try to edit a key in the Registry editor, the operation is interrupted by the Cannot create value: Error writing to the registry or Cannot edit value_name: Error writing the value’s new contents error messages. Such errors occur when the user account you are currently signed in to Windows 10 lacks the necessary privileges to edit the registry keys. They can be remedied by launching the Registry Editor as an Administrator and changing the default access permissions of the registry keys.
How To Open the Registry Editor as an Administrator
Open the Run command, type
and press Ctrl+ Shift + Enter to open the Registry Editor as an Administrator.
How To Change the Access Permissions of a Registry Key
If the problem still persists even after you've switched to administrator mode, the only solution is to take ownership of the registry key.
Open the Registry Editor and navigate to the desired key. Right-click on the key and select Permissions from the contextual menu displayed:
Click on the Advanced button:
Click on the Change button displayed next to Owner to open Select User or Group menu. Type the email address (Microsoft Account) associated with your current user account in the Enter the object name to select field and then click on Check Names:
Once the account has be validated, click on OK to change owner and then click on OK again to head back to the Permissions screen. Select the new owner (your current account) from the list and then tick the Allow checkboxes displayed next to Full Control and Read permissions:
Click on OK to close the Permissions window and return to the Registry Editor. You may now try to edit or create the desired value.