Hi, there! I got here because I had the same problem.
Just solved it: Relaunch Project. Here is the snippet in the "What's new" section:
Relaunch Project
If you are working on a project, and it fails to load or becomes completely unresponsive, you can relaunch the project. Depending on the underlying problem, relaunching the project may fix it and let you continue.
how to
Press the More (...) Button [upper right, next to settings] and choose Relaunch Project from the Project menu.