Hi Thank you for your question. This does not sound like an issue with the Firefox web browser, but more of an issue with the Mac operating system installed on your device. I recommend asking about this issue in a dedicated Apple support forum or service. I notice that you are using an older version of Firefox. I recommend that you update so that you have the latest security and stability fixes as well as new features. You can read more about how to update [https://support.mozilla.org/en-US/kb/update-firefox-latest-version here].