Solution
This can be caused by the serial device trying to use a COM port that's already used by a different device on your machine. To fix this, change your COM port assignments so there aren't any conflicts. You can change the COM port of the NI Serial device by consulting
this article , or you can change the COM port of the non-NI device:
- Right-click on the COM device entry in Windows Device Manager
- Select Properties
- Go to the Port Settings tab and click Advanced...
- Change the COM Port Number drop-down entry at the bottom of the Advanced Settings pop-up
If you try and change the COM port of the conflicting NI device using this Windows method, it won't work and you'll receive the error
There was an error renaming the COM port. The IOCTL call failed. You must use the NI Serial tool to change the NI device's COM port.