When you attempt to add an assembly reference to a Visual Studio project, the Add Reference dialog appears with a list of registered global assemblies in the .NET tab:

Add Your Assembly to Visual Studio

Unfortunately, adding your assembly to the Global Assembly Cache (GAC) does NOT make it automatically appear in the Visual Studio list of installed assemblies; you must add your assembly manually as follows:



  1. Run regedit to edit the Windows Registry.
  2. Navigate to the HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\.NETFramework\AssemblyFolders key.
  3. Right click on the AssemblyFolders key, then select New > Key. Enter the name of your assembly (without the .dll extension).
  4. Double click on the key's (Default) value. The Edit String dialog will appear. Enter the full path of the folder where your assembly resides. Note that all assemblies in that folder will appear in the Visual Studio list.
  5. IMPORTANT! You must exit and restart Visual Studio to see your assembly in the Add Reference dialog.

Multiple Versions of Same Assembly

Note that if you add multiple versions of the same assembly to the GAC, and you want all versions to appear in the Visual Studio list of installed assemblies, you have two options:

  1. Provide a different name for each version of the assembly, such as MyLib1.0.dll and MyLib2.0.dll, or
  2. Store each version of the assembly in its own folder, and add each folder to the registry as shown above.

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