If you try to use MSTest in VS 2012 or 2013 to run a VS test list created in VS 2010 all you get is this: Microsoft (R) Test Execution Command Line Tool Version 11.0.50727.1 Copyright (c) Microsoft Corporation. All rights reserved. Loading TestSettings1.testsettings... Loading TestStudioProjectToUpgrade.vsmdi... TestStudioProjectToUpgrade.vsmdi Value cannot be null. Parameter name: type Attached is sample project to reproduce the problem. To reproduce try running the command line: mstest /testmetadata:TestStudioProjectToUpgrade.vsmdi /testlist:list1 /testsettings:TestSettings1.testsettings The same command line works perfectly using VS 2010.