There are situations where you’re logged on to an administrator account, and want to work on the registry stuff only applicable to the current user (user registry hive). In those cases, you may find the UAC consent prompt an annoyance, since you know you’re only merging per-user stuff onto the registry. As a tweaker myself, I do face this little annoyance, but use a workaround to merge .REG files.
The trick is to add a "Merge (as User)" option to the right-click menu for .REG files, which should run the console tool REG.EXE. Here is how to do that.
Add "Merge (as User)" Context Menu Option for .REG files
1. Launch Regedit.exe to open the Registry Editor
2. Navigate to the following key:
3. Create a subkey named open2
4. Under open2, create another subkey named command
5. Select command, and assign the following data for the (default) value:
Note: If you need to see the output window every time, use the following data instead:
6. Exit the Registry Editor.
Editor’s Note: If the .REG file has instructions to modify a system-wide branch (say, HKEY_LOCAL_MACHINE) the REG.EXE console tool (running as standard user) encounters an ACCESS DENIED error, but simply proceeds onto the next entry in the .REG file to carry out rest of the instructions. However, the output reads "ERROR: Error accessing the registry", indicating that one or more of the registry keys/values as specified in the .REG could not be updated.