The command line for the TestStand 3.0 sequence editor and operator interfaces support the below options, so try using "testexec /run MainSequence c:\myfile.seq".
Scott Richardson
-------------------------------------------------------
testexec.exe 
             [
]
             [/run  ]
             [/runEntryPoint  ]
             [/quit]
             [/setCurrentDir]
             ...
      :  sequence file to open
      :       sequence to run
      :    entry point to run
Multiple sequence files, sequences, and entry points can be specified.
Quotes are required for arguments that contain a space, such as "Test UUTs" and "C:\My Documen
ts\Test Sequence.seq"
Application specific command line arguments must appear after the above supported arguments. 
					
				
			
			
				
	Scott Richardson
https://testeract.com