running regsvr32 c:\windows\system32\mmcndmgr.dll corrected the error and I was able to open mmc. http://support.microsoft.com/kb/296241 gives these steps to correct the error To determine whether this certificate has been removed from the system, follow these steps: 1. Locate a Windows 2000-based computer that exhibits these symptoms. 2. Click Start, click Run, type mmc, and then click OK. 3. In the Microsoft Management Console, click Console, and then click Add/Remove Snap-in. 4. In the Add/Remove dialog box, click Add. 5. Click Certificates, and then click Add. 6. Click Computer Account, and then click Next. 7. Click Local Computer, and then click Finish. 8. Click Close, and then click OK. 9. In the console tree, double-click Certificates (Local Computer). 10. Double-click Trusted Root Certificate Authorities, and then click Certificates. 11. In the details pane, locate the No Liability Accepted certificate. If the certificate is missing, follow the steps in the "Resolution" section to export the certificate from another workstation and import it. I am able to open mmc and go until step 4. But there is no CERTIFICATES in the add/remove dialog box. I only have Activex control Disk Managment Folder Link to web address How do I get certificates?