Debugging in an operating system with multiple subsystems

A facility for debugging in an operating system with native and non-native subsystems is described. The facility employs a debugger designed for use with the native subsystem. The debugger receives an indication to debug the application program of the non-native subsystem, attaches to the application program of the non-native subsystem, and when it receives an indication that the application program has started a new process, attaches to an executable component operating in the new process. When the debugger is appropriately configured, the facility attaches to an application program operating on the non-native subsystem rather than a terminal component operating on the native subsystem. When the debugger is appropriately configured, the facility redirects exceptions the debugger receives to the non-native subsystem.