Error -209838 Synchronization Lock Lost When Running an Executable Not Using TSN Capabilities

Updated Feb 5, 2024

Reported In


  • cDAQ-9185
  • cDAQ-9189
  • cRIO-9047


  • LabVIEW


  • NI-DAQmx

Issue Details

When using DAQmx Read or DAQmx Write functions with a TSN-enabled controller, I receive error -209838:


Error -209838 occurred at

Possible reason(s):

Synchronization lock was lost during operation. If the occasional loss of synchronization is acceptable, change the Synchronization Unlock Behavior property to ignore sync loss. Otherwise, go to for more information about sync loss management.

I am not interested in synchronization. How can I disable it?


Add a DAQmx Channel Property Node to the task, select the General Properties >> Synchronization Unlock Behavior property and set it to Ignore Lost Sync Lock.

This property will only appear if you have a TSN-enabled controller (such as the cDAQ-9189 or cRIO-9047) configured in NI MAX. To add this property without needing a TSN-enabled controller, see DAQmx Property Node is Missing Properties .

Additional Information

A TSN-enabled cDAQ or cRIO will create a synchronization domain by default. The error may occur from another device on the network being assigned as part of an automatic TSN network and then being disabled, reconfigured, or otherwise changed during communication. 
This solution is applicable only via API, it is not possible to set it via NI MAX.