For legacy debugging on Windows XP (32-bit) only, PortMon remains useful, but Error 2 almost always points to a missing, locked, or misconfigured port – never the tool itself. PortMon Error 2 is not a bug in PortMon – it is Windows telling you that the requested serial port cannot be opened. The error code is a direct pass-through from the CreateFile API.
This post breaks down exactly what this error means, why it happens, and the precise steps to resolve it. PortMon is a kernel-mode driver tool that intercepts and logs all interactions with COM (serial) and LPT (parallel) ports. It hooks into the Windows I/O subsystem to display IRP_MJ_WRITE , IRP_MJ_READ , and IOCTL calls. portmon error 2
| Tool | Platform | Supports USB? | Free | |------|----------|---------------|------| | (Eltima) | Windows 10/11 (x64) | Yes | No | | Free Serial Port Monitor (HHD Software) | Windows 10/11 | Yes | Yes (limited) | | com0com + Wireshark | Windows (x64) | Yes | Yes | | socat (Linux) + Serial to network | Cross-platform | Yes | Yes | | PySerial + logging wrapper | Any Python | Yes | Yes | For legacy debugging on Windows XP (32-bit) only,
However, one of the most common and frustrating errors users face is : "The system cannot find the file specified." This post breaks down exactly what this error
If you are a legacy systems administrator, a reverse engineer, or a developer maintaining older Windows applications, you have likely encountered PortMon (PortMonitor). This Sysinternals tool, while retired by Microsoft, remains invaluable for debugging serial and parallel port activity on Windows XP, Vista, and older Server editions.
mode com1: baud=9600 parity=n data=8 stop=1 Or use a PowerShell snippet: