Solution
This error is displayed if the file is not in the supported XML format or version (TestStand 4.0, 4.1, 4.2, 2010, 2010 SP1, 2012, 2012 SP1, 2013 or 2014). To save the sequence file in a supported version as an XML file, refer to
View Sequence Files on a Machine Without TestStand Installed. Then, retry opening the file in Sequence File Viewer.