uninstall Firefox. Then Delete the Mozilla Firefox Folders in C:\Program Files and C:\Program Files(x86) Then restart system. Note: your Firefox Profile is saved. But you should make a back up before you do : https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles

Reinstall with Current Release Firefox 57.0.2 with a Full Version Installer https://www.mozilla.org/firefox/all/

Please let us know if this solved your issue or if need further assistance.

Just finished with the fresh re-install as directed. Unfortunately that did not solve the problem. Opening new Tabs still resets the volume levels for those new Tabs to 100% in the Windows Volume Mixer.

Another thing I noticed is that sometimes the slider in the Volume Mixer "appears" to still be in the correct place, but the actual volume level in new Tabs is still reset to 100% every time one is opened (opening the Volume Mixer and clicking the volume slider puts it back at the correct volume).

Existing Tabs maintain the correct volume levels once they are set in the Mixer (20%, for example) no matter how many new Tabs are opened or how many subsequent web pages are visited using that Tab, but every newly opened Tab always has it's volume levels reset to 100%.

As an immediate workaround, lower the Device output slider (first column in screenshot). That puts a cap on all the individual Application sliders.

There is a bug on file to consolidate all of Firefox's various processes to a single slider, but this work is not done yet; maybe in Firefox 58.

If you find the number of visits to the volume mixer intolerable, you could reduce the number of content processes Firefox creates. This article will guide you to that setting: Firefox's performance settings.

A workaround I use personally is a user script that looks for media players in the page and sets their volume to 50%. If you want to try it, I can give more info.

58.0.1 here and problem still exists.

hey.toast said

58.0.1 here and problem still exists.

I have this problem too, it's absolutely insane that it something this simple hasn't been resolved yet. There's a bug listing for this that goes all the way back 10 months ago. https://bugzilla.mozilla.org/show_bug.cgi?id=1358372

I just recently switched to Firefox from Chrome, and this is driving me up a wall. Makes me want to switch back. I use volume mixer to adjust the volumes of every program and scale each one to each other for a reason.

Hi dpunk3, an initial fix to bug 1358372 is being discussed here: https://www.reddit.com/r/firefox/comments/7w3nv7/firefox_nightly_finally_only_creates_one_process/

It's not going to be in any Firefox 58 update; cross your fingers for Firefox 59.

jscher2000 said

Hi dpunk3, an initial fix to bug 1358372 is being discussed here: https://www.reddit.com/r/firefox/comments/7w3nv7/firefox_nightly_finally_only_creates_one_process/ It's not going to be in any Firefox 58 update; cross your fingers for Firefox 59.

More like Firefox should cross it's fingers I bother to come back after 59.