Freezing while attempting UI recording?

I have a week old project for macOS that I wanted to start UI testing. Unfortunately, whenever I try to start UI recording, the application freezes whenever anything is clicked (windows, menu bar, etc.). Starting a new project, however, works without problems.

1. Open project
2. Go to Test navigator
3. Right-click and choose "New UI Test Target…"
4. Hit Enter
5. Put cursor inside "testExample()" method in new Test Case source file
6. Hit record button at bottom of screen
7. Click in new window

Expected result:

Code inside "testExample()" updates

Actual result:

Running app freezes, then shows spinning beach ball.

Any ideas would be appreciated. Thanks!

macOS 10.12.3

Xcode 8.2.1