So those crashes all seem related to the Flash Player Plugin.

I'd suggest uninstalling Flash player, and seeing if you can live without it. Most websites that used to use Flash are now switching to HTML5, it's possible you won't even notice Flash player being gone (I uninstalled it myself months ago, and haven't noticed any issues.)

You can check for issues caused by plugins.

• set plugins to "Ask to Activate" on the about:addons page ("3-bar" menu button or Tools -> Add-ons -> Plugins)
• plugins are not affected by Firefox Safe Mode

When multi-process windows in Firefox is enabled then Firefox will use more memory and may be less responsive.

You can try to modify multi-process settings to see if this has effect.

• set dom.ipc.processCount to 1 if it is currently set to a higher value (4)
• disable multi-process windows in Firefox

You can disable multi-process windows in Firefox by setting these prefs to false on the about:config page.

• browser.tabs.remote.autostart = false
• browser.tabs.remote.autostart.2 = false

You can open the about:config page via the location/address bar. You can accept the warning and click "I'll be careful" to continue.

• http://kb.mozillazine.org/about:config

• http://www.ghacks.net/2016/07/22/multi-process-firefox/

Tyler Downer said

So those crashes all seem related to the Flash Player Plugin. I'd suggest uninstalling Flash player, and seeing if you can live without it. Most websites that used to use Flash are now switching to HTML5, it's possible you won't even notice Flash player being gone (I uninstalled it myself months ago, and haven't noticed any issues.)

I uninstalled flash just now, but the crash is still occurring, unfortunately.

cor-el said

You can check for issues caused by plugins.

• set plugins to "Ask to Activate" on the about:addons page ("3-bar" menu button or Tools -> Add-ons -> Plugins)
• plugins are not affected by Firefox Safe Mode

When multi-process windows in Firefox is enabled then Firefox will use more memory and may be less responsive. You can try to modify multi-process settings to see if this has effect.

• set dom.ipc.processCount to 1 if it is currently set to a higher value (4)
• disable multi-process windows in Firefox

You can disable multi-process windows in Firefox by setting these prefs to false on the about:config page.

• browser.tabs.remote.autostart = false
• browser.tabs.remote.autostart.2 = false

You can open the about:config page via the location/address bar. You can accept the warning and click "I'll be careful" to continue.

• http://kb.mozillazine.org/about:config

• http://www.ghacks.net/2016/07/22/multi-process-firefox/

I set both autostarts to false, and made sure the processcount was at 1 (it was), but it seems to have made it worse; the crash now crashes the whole browser instead of the tab. For now I've turned both autostarts back on (only autostart.2 was enabled when I checked, for some reason).

Also, the only plugins I have are OpenH264 Video Codec and Widevine Content Decryption Module, and I can't change either from "Always Active" to "Ask to Activate". OpenH264 mentions being automatically installed by Mozilla, and I don't remember installing Widevine, are these default plugins?

Here are the crash reports after doing both of these: bp-a2851d56-9ede-4fcf-8be9-451670170811 bp-5afe9ab1-1f40-4a66-bfe8-3ed421170811

And the crash report after turning both autostarts on: bp-67aa83e2-026a-4f37-bc04-598dc1170811

Did a bit more work on it. Checked that videos worked with Chrome. Yup. Uninstalled Firefox and refreshed it (made sure my account didn't sync) and...it worked. I synced my account and I was having issues again, so I'm forced to assume that I've got something odd going on with my settings or addons, so I'll just work through that. Thanks for all your help here though, I really appreciate you two taking the time to help me :)

EDIT: That seemed to have been a fluke. Went through it again, and I'm still having issues. Officially really confused lol

Two of those last three crash reports point to a potential incompatibility with your nVidia graphics card driver software. Could you try this: Upgrade your graphics drivers to use hardware acceleration and WebGL.

jscher2000 said

Two of those last three crash reports point to a potential incompatibility with your nVidia graphics card driver software. Could you try this: Upgrade your graphics drivers to use hardware acceleration and WebGL.

Thanks, this put me on the right track! Went ahead and did a fresh install of the drivers (not using the driver updater thing on my computer, just took the latest ones straight from the website), didn't work. Turns out it's a known problem with this specific driver, and while rolling back didn't work for me, I know it's a problem with the driver itself so I guess I just gotta wait for them to release a new version and fix the issue. Thanks a ton!

As a temporary workaround, you could try disabling Firefox from using hardware acceleration. Either:

Windows: "3-bar" menu button (or Tools menu) > Options Mac: "3-bar" menu button (or Firefox menu) > Preferences

In the left column, click Advanced. On the right side, with the "General" mini-tab active, uncheck the box for "Use hardware acceleration when available".

This takes effect the next time you exit Firefox and start it up again. Note that fonts may be rougher-looking and some map sites may work poorly with this setting.

Unfortunately, I already have hardware acceleration off, so no dice ):