I've referenced the MSMQ v3 Object Library in a VS2010 C# project only to get: System.Runtime.InteropServices.COMException (0x80040154): Retrieving the COM class factory for component with CLSID {0188401C-247A-4FED-99C6-BF14119D7055} failed due to the following error: 80040154 Class not registered (Exception from HRESULT: 0x80040154 (REGDB_E_CLASSNOTREG)). I've registered the library the reference points to: regsvr32 C:\windows\system32\mqoa.dll What am I missing? Assuming this works, what will I have to do at deployment to ensure the app will run on other machines with MSMQ installed?