Permits or prohibits use of this snap-in.If you enable this setting the snap-in is permitted. If you disable the setting the snap-in is prohibited.If this setting is not configured the setting of the "Restrict users to the explicitly permitted list of snap-ins" setting determines whether this snap-in is permitted or prohibited.-- If "Restrict users to the explicitly permitted list of snap-ins" is enabled users cannot use any snap-in except those explicitly permitted. To explicitly permit use of this snap-in enable this setting. If this setting is not configured (or disabled) this snap-in is prohibited.-- If "Restrict users to the explicitly permitted list of snap-ins" is disabled or not configured users can use any snap-in except those explicitly prohibited. To explicitly prohibit use of this snap-in disable this setting. If this setting is not configured (or enabled) the snap-in is permitted.When a snap-in is prohibited it does not appear in the Add/Remove Snap-in window in MMC. Also when a user opens a console file that includes a prohibited snap-in the console file opens but the prohibited snap-in does not appear.
Windows Components\Microsoft Management Console\Restricted/Permitted snap-ins
User
At least Windows Server 2003 operating systems or Windows XP Professional
HKCU\Software\Policies\Microsoft\MMC\{C96401CF-0E17-11D3-885B-00C04F72C717}!Restrict_Run
MMC.admx