When you face the freeze/stop response issue during editing with Filmora, please take a dump and send it to us to do further troubleshooting here.
For win:
Follow this article to create and collect dump.
For Mac:
1. At the moment Filmora is not responding, open the Activity Monitor application (from the Utilities folder inside your Applications folder). Select the Filmora application from the list. To find it easily, search for it using the search field at the top right. Click the Action pop-up menu (looks like a gear) in the toolbar, then select Sample Process.
2. A new window will open to display the sample. Like this:
3. When Activity Monitor finishes sampling, click Save… to save the result as a text file.