Error 1073807194 When Communicating Over Serial Port in VISA Session

Updated May 29, 2026

Reported In

Software

  • LabVIEW Full
  • LabVIEW
  • LabVIEW Base

Driver

  • NI-VISA

Issue Details

I am getting LabVIEW VISA Error 1073807194 and the only way to reopen the VISA session is to close and open LabVIEW. How can I access my serial port and prevent this in the future? 

Solution

This error occurs when you are trying to access a VISA session that is already in use. 

To close VISA sessions that are open: 

  1. View the sessions that are left open and close them using the VISA Close VI to end the specific VISA session when you are done using it within your code. If you do not close your VISA reference, the computer will continue to reserve that port until you close LabVIEW.
  2. Close and reopen LabVIEW to release all open VISA sessions. When LabVIEW closes, it closes all open VISA sessions until they are reinitialized next time your LabVIEW code runs.

Additional Information

To see a properly built example using VISA Close, see the LabVIEW example GPIB with VISA functions in the LabVIEW example finder. 

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