PRB: Class Not Registered Error and Empty Components Dialog

When you choose to view the Component dialog in Microsoft Visual Basic, either by clicking on the Project menu and selecting Components or by using the activation keys CTRL+T, the following error appears: After clicking OK, the Component dialog opens and no components are displayed.

The Microsoft Component Category Manager Library, ComCat.DLL, is incorrectly registered.

Correctly register ComCat.DLL using RegSvr32.Exe, a utility program that ships with Visual Basic and allows you to register DLL's and other files into the system registry.

To correctly register ComCat.DLL, follow the steps below:

1. Verify that ComCat.DLL is located in the Windows 95 or Windows 98 Windows\System folder or in the Windows NT Windows\System32 folder. If ComCat.DLL can not be located, copy it from the Visual Basic installation media into the appropriate folder.
2. From the Start menu, choose Run.
3. Type the following command into the Run dialog, replacing <Path To Windows\System(32)> with the full path to your Windows\System folder:
   RegSvr32.Exe <Path To Windows\System(32)>\ComCat.DLL

OLE groups all components into functional categories called Component Categories. ComCat.DLL is used to identify the areas of functionality that a component may support and provides the functionality to register and unregister components into specific Component Categories. Therefore, when Visual Basic opens the Components dialog it can categorize the components into Controls, Designers and Insertable Objects without displaying every object and class registered on the system.

Steps to Reproduce Behavior

1. Unregister ComCat.DLL using RegSvr32.Exe:
   RegSvr32.Exe /U <Path To Windows\System(32)>\ComCat.DLL
2. Start Visual Basic, and create a new Standard EXE project.
3. From the Project menu, choose Components. The error message described above occurs. Note that when you click OK, no components are displayed.

For additional information, please click the article number below to view the article in the Microsoft Knowledge Base: