What does Windows error code 1118 (ERROR_SERIAL_NO_DEVICE) mean?

 
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ERROR_IO_DEVICE ERROR_IRQ_BUSY

ERROR_SERIAL_NO_DEVICE

No serial device was successfully initialized. The serial driver will unload.

ERROR_SERIAL_NO_DEVICE is decimal 1118 (0x45E). It is associated with serial-driver startup rather than an ordinary failed read or write. Windows attempted to initialize the serial device set handled by a driver, but none became usable, so the driver could not remain active for those devices.

Contexts in which it matters

  • legacy motherboard UARTs or add-in serial adapters during boot or device start
  • USB-to-serial adapters whose bus device exists but whose function driver cannot start
  • virtual COM ports presented by a hypervisor, remote-console product, modem stack, or industrial gateway
  • custom serial drivers that discover multiple ports and fail every initialization attempt

An application opening COM3 may only see a later “file not found” or device error. Error 1118 can be recorded earlier by the driver or Plug and Play path, so diagnosis often requires looking beyond the application log.

What to collect

  • device instance ID, hardware IDs, compatible IDs, assigned COM number, and driver package version
  • Device Manager problem code and problem status
  • SetupAPI device-install log entries for the affected instance
  • ACPI, PCI, USB, or virtual-bus resources presented to the serial function
  • driver, Kernel-PnP, and bus-controller events from the same boot

For embedded or non-PnP hardware, also record firmware configuration, UART base address, interrupt assignment, clock, and whether another operating system or bootloader can access the port. For a VM, preserve the virtual hardware definition and host-side backing device.

Common causes

  • the hardware is disabled in firmware or absent from the machine
  • the selected driver package does not match the device or failed its start routine
  • required I/O, interrupt, connection, or bus resources were not supplied
  • a virtual serial endpoint points to a missing pipe, socket, or host device
  • all ports managed by a multiport adapter failed self-test or initialization

Changing baud rate or parity in the application does not fix this condition because the device never reached normal communications setup. First establish that the device stack starts and exposes a usable communications resource.

Recovery approach

Rescan or restart the device only after correcting the underlying configuration. Reinstalling the same driver repeatedly without examining the Plug and Play status can erase useful timing evidence while leaving the root cause unchanged. On production industrial systems, coordinate any driver restart because serial ports may control physical equipment.

Software that depends on optional serial hardware should degrade explicitly: mark the port unavailable, preserve the device identity, and retry on a PnP arrival event rather than polling CreateFile continuously.

Distinguishing nearby serial errors

ERROR_IRQ_BUSY identifies a resource-sharing conflict. ERROR_MORE_WRITES and ERROR_COUNTER_TIMEOUT describe completion reasons for an XOFF counter request after a port is already operational. Error 1118 is earlier and broader: no serial device controlled by the driver initialized successfully.

Example

After a hypervisor migration, a VM still contains a virtual COM port configured to use a host named pipe that does not exist on the destination host. The guest serial driver cannot initialize the presented endpoint and records 1118. Updating application COM settings is ineffective; the virtual hardware backing must be corrected or the unused port removed.

References

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