The default Firefox notification system doesn't notify you with audio, only visually. As you have no audio problems with e.g. YouTube and Facebook, you may have to contact the developer(s) of the add-on(s) that you're using.

Thanks for your reply. Since all the addons with sound notifications have gone silent at the same time it seems unlikely that the problem lies with any particular addon.

gj999 said

Thanks for your reply. Since all the addons with sound notifications have gone silent at the same time it seems unlikely that the problem lies with any particular addon.

As you say that this only happens with notifications and that audio on sites like YouTube is fine, I can only think of the extensions in question causing this (how unlikely it may seem). You also say that disabling all other add-ons makes no difference, which makes me rule out something like e.g. NoScript causing this.

I can only hope that somebody else will come up with the perfect solution for you (sorry ..... )

Thanks for your input.

gj999 said

Thanks for your input.

So far I haven't been of any help ......  :(

I couldn't let it go just yet and I was thinking that maybe you could check Windows Settings => System ...... (?)

Or - in case you're using Thunderbird, you could post a question on their support forum :

https://support.mozilla.org/en-US/products/thunderbird

(click on 'Ask a Question' at the top of the page)

Windows system settings all look normal/default, also I am getting notification sounds from Chrome extensions so I think it an FF issue. I'm not using Thunderbird.

Hi, I've now tracked down the issue and the fix. For some reason media.autoplay was marked as false, now fixed. Thanks for your input.