Unable to modify registry as admin on Windows 2012

Question

On Windows 2012, I'm trying to change the AppIDFlags value in the registry key HKEY_CLASSES_ROOT\AppID\{E62A7A31-6025-408E-87F6-81AEB0DC9347} to allow interaction with the desktop as documented here: http://forums.arcgis.com/threads/69842-Debugging-your-SOE-on-Windows-8

However, even when running regedit.exe as administrator I'm not allowed to change the value or take ownership of the registry key. On saving the value it says:

Cannot edit AppIDFlags: Error writing the value's new contents.

When trying to take ownership of the key, I get this error:

Unable to set new owner on {E62A7A31-6025-408E-87F6-81AEB0DC9347}

Access is denied.

Why am I not allowed to make any changes to the registry as administrator?

Solution

Apparently some process was having a handle open to the registry key. After rebooting I was able to edit the value.

Comments

[Ryan Ries]

Perhaps using something like Process Explorer, you could check and make sure that no other process on the system has a handle open to that key already?

[MvdD]

That must have been it. A reboot made the issue go away. Thanks!

[MrGigu]

@user18044 if you have resolved this issue, you might want to consider posting your resolution as an answer and giving yourself the check-mark so that this question doesn't float around as un-answered for the rest of time.