For a technician encountering Error 2, the solution is rarely a simple reinstall. First, one must verify the existence of a physical or virtual serial/parallel port. In a virtual machine (e.g., VirtualBox, VMware), adding a virtual COM port may resolve the error. Second, for 64-bit systems, the only reliable solution is to use an alternative, modern tool such as from Eltima Software or the built-in PowerShell commands (e.g., Get-WinEvent with query filters). Third, as an unsupported workaround, one can run Portmon inside a 32-bit virtual machine running Windows XP or older, where driver signing was not enforced. None of these solutions "fix" Portmon; instead, they accommodate its obsolescence.
The "portmon.exe error 2" is a perfect case study in software entropy. It is not a bug, but a breaking of context. The error persists because the tool’s assumptions about the hardware landscape (ubiquitous COM ports), the operating system architecture (unsigned kernel drivers allowed), and the security model (unrestricted I/O access) no longer hold true. For the modern administrator, encountering Error 2 should serve as a signal to retire Portmon and adopt contemporary monitoring solutions. To attempt to force Portmon to run on a standard Windows 10/11 64-bit machine is to engage in a losing battle against two decades of operating system evolution. The error message, in its stark brevity, tells the user exactly what is wrong: the file—be it the port device, the driver, or the past—cannot be found. portmon.exe error 2
Even on systems that possess legacy ports (e.g., industrial PCs or virtual machines with emulated COM ports), Error 2 frequently appears. This is due to the kernel-mode driver component. Original versions of Portmon contained an unsigned 32-bit driver. Starting with Windows Vista and solidifying in Windows 10/11 (64-bit), Microsoft enforced mandatory driver signing and implemented Kernel Patch Protection (KPP), also known as "PatchGuard." The operating system refuses to load an unsigned driver into the 64-bit kernel. When Portmon attempts to start its driver and the kernel blocks it, the driver framework returns ERROR_FILE_NOT_FOUND because the driver file is either not loadable or the associated device object cannot be created. In this context, "Error 2" is a mask for a security policy violation. For a technician encountering Error 2, the solution