If user builds several players to the same project folder on Windows and keep players running, errors appear.

To repro:
1. Create a project.
2. Press Build and Run, save scene and exe.
3. Keep player running.
4. Return to Unity and press Build and Run again.

Actual result: Data folder is not created.
If several players build this way are running, CPU is 100% loaded and Windows fails.
Errors in log:

IOException: Sharing violation on path Temp\StagingArea\UnityPlayer.dll" or "D:\UnityProjects\ws-echo1\UnityPlayer.dll
System.IO.File.Copy
Build completed with a result of 'Failed'
UnityEditor.BuildPlayerWindow+BuildMethodException: 3 errors

Expected result: Fewer players should be built with no errors.

As potential solution, UnityPlayer.dll should be moved to Data folder.

Behaviour changed in 2017.2.0a1.
Works as expected in 2017.1.1.f1