For .Net Framework 4.5 and above, you can use the Exception.HResult property: int hr = ex.HResult; For older versions, you can use Marshal.GetHRForException to get back the HResult, but this has significant side-effects and is not recommended: int hr = Marshal.GetHRForException(ex);
You can use _com_error: _com_error err(hr); LPCTSTR errMsg = err.ErrorMessage(); If you don’t want to use _com_error for whatever reason, you can still take a look at its source, and see how it’s done. Don’t forget to include the header comdef.h
Update for those who got this issue for VS2013 or VS2015 after upgrading a VS200X setup project using the Microsoft Visual Studio Installer Projects extension. Following the recipe for v1.0.0.0 from MS finally made it work for me: Microsoft Visual Studio Installer Projects Unfortunately we couldn’t address all cases of the command line issue for … Read more