In Windows system error codes (Win32 Error Codes), corresponds to ERROR_FILE_NOT_FOUND . In the context of Portmon, this does not mean your portmon.exe file is missing. It means that a critical dependency required by Portmon cannot be located .

Original Portmon is a . On a 64-bit version of Windows , loading a 32-bit kernel driver is strictly forbidden. When Portmon tries to call CreateService for its 32-bit driver, the OS returns Error 2 (disguising the real "Bad Image Format" error as a file-not-found for security reasons).

Are you working with a or a USB-to-Serial adapter ? Knowing the hardware type can help narrow down a better software alternative.

Install the service manually.