We recently switch from Visual Studio 2013 to 2015, same goes with Microsoft Test Manager.
I created CodedUI test in the same way that i was creating it in VS2013. Associated it with test case and then try to run it as Automated Test from Microsoft Test Manager. Unfortunately i keep getting this error:
Error adding test case  to test run: Unable to load the test container '\NAS\UTV\TFS2012\NOO\Automated Tests\Automated Tests\Automated Tests_20160310.5\testcodedui.dll' or one of its dependencies. Error details: System.IO.FileNotFoundException: Could not load file or assembly 'Microsoft.VisualStudio.TestTools.UITesting, Version=126.96.36.199, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. The system cannot find the file specified.
Typically Your 2013 Test agent comes with the libraries for Coded UI 2013 (V12), when you create a test these references are added automatically by Visual Studio.
In your case, you have 2015 VSTS, ergo references of Coded UI from 2015 (V14) will be in your test. But, when you run the test, your 2013 agents will not able to find the references you have in your test. TO fix this, you will need to remove all coded UI refrence which are added by default and add your Own.
There are couple of implicit reference in Coded UI (Reference of your references) You can identify them from this link
Add them to your lib folder as well.
After this, associate your test, hopefully it should run. If u still get any missing file error, then you are missing a implicit reference. Just search for in your programfiles directory of 2015 VSTS and add to your project refrence thru lib folder. It should work !!