TestStand Could Not Load File or Assembly

Updated Dec 2, 2019

Reported In


  • TestStand 2012
  • TestStand 2012 SP1
  • TestStand
  • TestStand 2016
  • TestStand 2016 SP1

Issue Details

I recently uninstalled TestStand 201x SP1, then reinstalled TestStand 201x (without SP1). I receive the following error when launching the TestStand Sequence Editor:

Could not load file or assembly 'TSDotNetSupport, Version=, Culture=neutral, PublicKeyToken=ad9244eb3b825cd8' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040

Why is this occurring, and how can I fix it?


This error occurs because the TestStand 201x SP1 Sequence Editor and User Interfaces updates configuration files to a state that is incompatible with TestStand 201x.  When TestStand 201x attempts to launch using an updated configuration file, the error occurs.

To correct the issue, follow the steps below:
  1. Delete or back up the SeqEdit.xml and UserInterface.xml files, and the layout_current.bin and layout_current_old.bin files if they exist, located by default at the TestStand Local Application Data folder
  2. Launch the TestStand 2012 Sequence editor.  The SeqEdit.xml and UserInterface.xml files will be regenerated, and TestStand will launch successfully.

Additional Information

These files contain configuration options for the sequence editor and user interfaces, such as panel size and font settings used on the Insertion Palette pane and the Variables pane, and the current user's layout for the sequence editor.  If you plan to install TestStand 201x SP1 again in the future, consider backing up these files for use at that time.