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Fix Erratic Mouse Pointer Caused by FTDI USB Serial Adapter (GPS NMEA Issue)

In some computers running Windows 11, 10, or 7 (32-bit or 64-bit), using an FTDI USB serial adapter while a GPS receiver is streaming NMEA data may cause the mouse pointer to behave erratically.
This occurs because Windows can incorrectly interpret incoming NMEA messages as input from a serial mouse.
Click the images below for a larger view.
Device Manager with the FTDI USB Serial Port context menu open and Properties selected
Figure 2
Device Manager showing the FTDI USB Serial Port under Ports COM and LPT
Figure 1

Symptoms

You may experience the following when a GPS receiver is connected via an FTDI USB serial adapter:
  • Mouse pointer moves randomly across the screen
  • Cursor jumps or clicks without user input
  • System becomes difficult to control
  • Issue starts immediately after connecting the GPS device

How to Fix the Problem

To resolve this issue without restarting the computer, disable the Serial Enumerator setting for the affected COM port.
USB Serial Port Properties window with the Port Settings tab and the Advanced button
Figure 3
Windows 11 / 10 / 7 (32-bit or 64-bit)
  1. Open Device Manager
    • Press Windows Key + X and select Device Manager
    • Or, search for "Device Manager" in the Start menu
  2. Expand Ports (COM & LPT)
  3. Locate the COM port associated with the FTDI USB serial adapter (Figure 1)
  4. Right-click the port and select Properties (Figure 2)
  5. Go to the Port Settings tab
  6. Click Advanced (Figure 3)
    7. Advanced Settings window with Serial Enumerator cleared and ready to save
    Figure 5
    Advanced Settings window showing the Serial Enumerator checkbox enabled by default
    Figure 4
  7. Uncheck Serial Enumerator (Figures 4 & 5)
  8. Click OK to apply the changes

Additional Notes

  • The setting applies to the specific COM port only
  • Windows may reset this setting after a restart
  • If the issue returns, repeat the procedure
  • For USB multi-port adapters, apply this setting to each COM port individually

Summary

Disabling the Serial Enumerator prevents Windows from misinterpreting GPS NMEA data as mouse input, eliminating erratic cursor movement when using FTDI USB serial adapters.

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