Steps to reproduce:
1) Open the attached project.
2) Open scene 'testScene.unity'.
3) Go to /Assets/Resources/DontWant and select an image named 'XboxOne_Button_A'.
4) In the menu bar, press Build > Move Resources and Build Test.
- Wait for the building process to finish.
5) Repeat step 4.
- Unity hangs in the middle of the building process.

*Note: this hang appears to be caused by moving one of the materials from /Resources/DowntWant to /Resources_EXCLUDED/DontWant between the builds.
*Note#2: further attempts to build the project after restarting Unity fail, unless the Library folder is deleted first.

Reproduced on:
5.4.0b18, 5.3.4p1

Did not reproduce:
5.2.2f1