FCPX suddenly became unusable

FCPX suddenly became unusable. It constantly freezing forcing me to force quit the app. Im only working with a 5 minutes MPEG-4 movie I downloaded from youtube. I cant even play it back or skip ahead (or do anything) without the entire app freezing. Even clicking the top menu.

MacBook Pro 16″, macOS 15.6

Posted on Aug 1, 2025 8:13 PM

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Question marked as Top-ranking reply

Posted on Aug 2, 2025 2:04 AM

Whenever the application crashes you must delete the preferences. To delete preferences, hold down command and option while starting the application and click Delete Custom Settings. The application will start with default settings and open an “Untitled” library. Adjust the settings, reopen the library you were working, and see how it works now.


If the issue persists and it is happening specifically with one file then transcoding it may help, as already advised. If it still persists Please run Etrecheck and post its full report here.

Use the “additional text” button and paste the report into the text box.

4 replies
Question marked as Top-ranking reply

Aug 2, 2025 2:04 AM in response to colby39

Whenever the application crashes you must delete the preferences. To delete preferences, hold down command and option while starting the application and click Delete Custom Settings. The application will start with default settings and open an “Untitled” library. Adjust the settings, reopen the library you were working, and see how it works now.


If the issue persists and it is happening specifically with one file then transcoding it may help, as already advised. If it still persists Please run Etrecheck and post its full report here.

Use the “additional text” button and paste the report into the text box.

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FCPX suddenly became unusable

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