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Original poster
Oct 8, 2013
So, updated to High Sierra Public Beta today, and everything works like a charm - Except Firefox.

No sound at all.

Plugins updated. Music from itunes and all other apps work fine.

Tried downloading a different version of Firefox and same result. A video from youtube plays, but not the sound.

Rebooted machine several times. Reset NRAM (or was it VRAM?) by holding option+cmd+r+p. Same result.

Anyone had a similar issue? Suggestions?

EDIT: Safari works fine. Seems Firefox has an issue with High Sierra.
Last edited:


macrumors newbie
Jul 6, 2012
There’s a bug logged for this on the Bugzilla, Bug 1376163 - [10.13] No audio playback on YouTube, no audio/video on Netflix (macOS High Sierra 10.13 Beta)

And there’s a fix.

Paul Adenot (:padenot) said:
Can someone try to re-enable e10s, and go to about:config, set "security.sandbox.content.level" to "0", restart the browser, and try again ?
Lou said:
This fixed my audio High Sierra beta 2.
Joe McCabe said:
Confirmed that e10s enabled and "security.sandbox.content.level" to "0" resolves the problem.

And for anyone who doesn’t know how to get to the about:config, just type about:config into the address bar. Much more detail from the Configuration Editor for Firefox article.

Depending on what version of Firefox you’re using and if you’re opted out of e10s (Mozilla’s cute short name for Electrolysis, their sandboxed browser engine tech), you may not have to re-enable e10s. This is what you might see in Firefox ▸ Preferences:

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