Substack video freezing since Firefox 154 update

Hi! Since the problem started after updating to Firefox 154 and mainly affects longer Substack videos, I’d first check whether Firefox’s hardware acceleration, extensions, or cached site data are involved.

Could you try these steps?

1. Test Troubleshoot Mode: Open Firefox’s menu → Help → Troubleshoot Mode… and play the same Substack video for 20–30 minutes. This temporarily disables extensions and some customizations. If the video no longer freezes, an extension or customization is likely involved. 2. Clear Substack site data: Open the Substack page, click the padlock/site information icon in the address bar, then clear the site’s cookies/site data and reload the page. 3. Check hardware acceleration: Go to Settings → General → Performance, uncheck Use recommended performance settings, and test with Use hardware acceleration when available disabled. 4. Make sure Firefox is fully up to date and restart Windows after the update.

If it still happens, please provide the exact Firefox version (including the build number from Help → About Firefox), your Windows 11 version, whether you use any extensions/content blockers, and ideally a specific Substack post where the problem can be reproduced.

Since the issue takes 15–30 minutes to appear, testing in Troubleshoot Mode for at least 30 minutes would be particularly useful.

Thanks for the suggestions. I disabled all extensions, and got through 3 or 4 thirty minute Substacks without freezing. Four of these I wasn't really using anyway, so I re-enabled the one I rely on (Ghostery) and I'll see how it goes.