Symptom: When you install a .NET Windows Service, it says there was no error. Yet, when you go to start the service, you get an "Error 193: 0xc1" message and subsequently, the process refuses to start. Cause: The binary you installed as a service is not a "Windows Application." Solution: Uninstall the old service, change the project output type to "Windows Application" and build it, install the new binary (should be *.exe), and start the service again. This is just one example of what can cause the error message.