TestStand Crashes When Executing a Second Sequence File That Uses the Same Code Module

Updated Feb 12, 2026

Reported In

Software

  • TestStand

Issue Details

When running multiple TestStand sequence files that reference the same code module, TestStand may crash when executing the second sequence file. This issue occurs consistently on the second execution, regardless of which sequence file is chosen first.

You may observe the following behavior:

  • The first sequence file runs normally with no errors.
  • When launching a second sequence file (even a different one), TestStand crashes immediately upon loading or executing steps that reference the same code module.
  • The crash occurs consistently on the second execution, even if the sequence files are selected randomly.

Example of the Error message when crash happen:

Solution

The crash occurs because the first sequence file does not unload the shared code module after executing, leaving the module locked in memory. When the second sequence attempts to load and execute the same code module, TestStand detects a conflict due to the module being locked, causing a crash instead of properly reloading the module. This is typically related to the Unload Option configuration in the sequence file properties.

 

To solve the issue you may need to configure the sequence file to unload code modules after execution by following the steps below:
 
  1. Open your sequence file in TestStand.
  2. Navigate to Edit → Sequence File Properties.
  3. Go to the General tab.
  4. Locate the Unload Option setting.
  5. Change the unload behavior to either:
    • Unload after step executes, or
    • Unload after sequence executes

These options ensure that the code module is unloaded before another sequence attempts to access it, preventing lock conflicts and crashes.

 

Additional Information

  • This issue commonly occurs when using DLLs, .NET assemblies, or LabVIEW code modules that do not support simultaneous load instances.
  • If your test architecture requires shared modules, ensure that your unload strategy is consistent across all sequences.

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