Why is vstest.console.exe suddenly giving me a warning about isolation mode?

Question

I have a Jenkins server running tests using vstest.console.exe. All of a sudden, between two builds with no change to the contents of the workspace, it is reporting that it is running in isolation mode:

10:52:38 D:\Program Files (x86)\Jenkins\workspace\Trunk>"D:\Program Files (x86)\Microsoft Visual Studio 14.0\Common7\IDE\CommonExtensions\Microsoft\TestWindow\vstest.console.exe" "src\Test\bin\Test.dll" /TestCaseFilter:"TestCategory!=ExcludeFromBuildServer" /Enablecodecoverage /UseVsixExtensions:false /Logger:trx 
10:52:38 Microsoft (R) Test Execution Command Line Tool Version 14.0.25420.1
10:52:38 Copyright (c) Microsoft Corporation.  All rights reserved.
10:52:38 
10:52:38 Starting test execution, please wait...
10:52:38 Warning: Using Isolation mode to run the tests as diagnostic data adapters were enabled in the runsettings. Use the /inIsolation parameter to suppress this warning.

There has certainly been no change in any runsettings file.

Maybe the server was restarted between runs. Can there have been any vstest.console.exe related update causing this? Is there a change in some default runsettings file?

I've also tried running the tests without the /Codecoverage switch and I've tried to specify a .runsettings file with DataCollectors empty and removed but I still get the dreaded Isolation mode.

Answer 1

This might mean that your test runner needs some other .NET platform or different architecture. Something is forcing it to run in the isolated mode. Have you changed your configuration management or something else on your project or solution? Try specifying /noisolation switch on MSTest.exe.