Add the /a switch to the command. For example:

mmc c:\winnt\system32\commgmt.msc /a

If you just launch MMC by itself, you'll get MMC help that explains this.

>When I load MMC from Windows 2000, I can get access to all menu options under Console. So, I can add additional Snap-Ins. However, if I start MMC with a .MSC setup, it loads the setup I save but the Console menu only contains an Exit option. How can I have MMC to load with a pre-defined setup so I can add more Snap-Ins?