Intermittent Serial Communication Issues on Windows 11

Mandhniya, Aakanksha (WP) 0 Reputation points
2026-07-24T13:26:01.64+00:00

Hello Team,

We are seeking assistance regarding an intermittent serial communication issue observed on Windows 11 systems.

Our customer uses payment terminals (Ingenico Lane/3600 and Verifone devices) that communicate with the POS application using serial communication. The same hardware setup, application, communication library, and terminal configuration work reliably on Windows 10. However, after migrating to Windows 11, intermittent communication issues have been observed.

Issues Observed on Windows 11

  • Connection errors between the application and the terminal
  • Data loss during command/request and response exchanges
  • Incomplete or interrupted responses from the device
  • Intermittent communication timeouts
  • Occasional failures in receiving complete terminal responses

Environment Details

  • OS: Windows 11
  • Communication Type: Serial COM Port
  • Terminals: Ingenico Lane/3600 and Verifone devices
  • Application uses serial communication through COM ports
  • No issues observed on Windows 10 using the same setup

Assistance Required

We would appreciate guidance on the following:

  1. Are there any known Windows 11 issues related to Serial communication that could result in data loss, incomplete reads, or communication timeouts?

Are there any Windows 11 specific updates, patches, or hotfixes recommended for applications communicating through COM ports?

Are there any recommended settings for:

  • COM Port communication
    • USB-to-Serial/VCOM devices
      • USB power management
        • USB Selective Suspend
          • Device power-saving features
            • Serial port buffering
            Have there been any changes in Windows 11 serial communication handling compared to Windows 10 that may impact legacy serial/VCOM-based applications? Are there any diagnostic tools, logging mechanisms, or troubleshooting steps recommended by Microsoft to identify intermittent serial communication issues on Windows 11?

Additional Observation

The issue is reproducible only on Windows 11. The same application, terminal firmware, communication configuration, and hardware setup operate successfully on Windows 10, which suggests the behavior may be related to Windows 11 serial/VCOM driver handling, power management, or COM port communication.

Any documentation, best practices, or troubleshooting recommendations would be greatly appreciated.

Thank you for your assistance.

Windows for business | Windows Client for IT Pros | Devices and deployment | Other
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  1. Hoang Le 1,045 Reputation points Independent Advisor
    2026-07-24T15:52:54.24+00:00

    Hello,

    Windows 11 has introduced changes in USB and COM port handling that can affect legacy serial communication, especially with USB-to-Serial adapters used by Ingenico and Verifone terminals. The intermittent timeouts and incomplete reads you’re seeing are consistent with issues reported when relying on the default Microsoft USB-to-Serial driver. The first step is to replace that driver with the official vendor-provided driver, which is optimized for these devices. Assign a fixed COM port number during installation to avoid dynamic reassignment.

    You should also disable USB Selective Suspend in Power Options and uncheck “Allow the computer to turn off this device to save power” in Device Manager for each USB Root Hub and COM port. This prevents Windows 11’s aggressive power management from interrupting communication. Confirm that baud rate and buffer settings match between your POS application and the terminal firmware.

    Windows 11’s updated I/O stack can cause dropped packets in applications that rely on tight timing. To verify, enable verbose logging in your communication library and use COM monitoring tools like Microsoft’s SerialTest to capture traffic. If issues persist even after driver and power adjustments, the root cause may be within Windows 11’s USB stack itself, in which case raising a support case with Microsoft is the recommended path.

    I hope you've found something useful here. If it helps you get more insight into the issue, it's appreciated to accept the answer. Should you have more questions, feel free to leave a message. Have a nice day!

    Hoang Le.

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