hi, thanks for reporting this. could you test if the following change fixes the hangs problem: go to the firefox menu ≡ > options > privacy & security panel and under permissions check the setting to prevent accessibility services from accessing your browser.

Tried this and it didn't work Plugin container still causes freeze

What plugin are you referring to?

NOT plugin it's "plugin container for Firefox" listed as an App or rateher sun-App in MS TaskManager. I don't know what that means so can't explain more. It's not listed a programme or App if saearched for in the normal way and is only seen in TaskManager when it causes Firefox to freeze. I guess it is present normally very briefy during transition from one web page to another and isn't seen unless there is a problem

The plugin-container process is used to run a plugin (Flash) in its own process in a sandbox.

You can check for issues caused by plugins and set the Flash plugin to "Ask to Activate" on the about:addons page ("3-bar" menu button or Tools -> Add-ons -> Plugins) Note that plugins are not affected by Firefox Safe Mode.

It is possible that your firewall or other security software blocks or restricts Firefox without informing you, possibly after detecting changes (update) to the Firefox application. Remove all rules for Firefox from the permissions list in the firewall and let your firewall ask again for permission to get full, unrestricted, access for Firefox and the plugin-container process and the updater process.

See:

• https://support.mozilla.org/en-US/kb/server-not-found-connection-problem
• https://support.mozilla.org/en-US/kb/Firewalls
• https://support.mozilla.org/en-US/kb/fix-problems-connecting-websites-after-updating

Boot the computer in Windows Safe mode with network support to see if that has effect in case security software is causing problems.

• http://www.bleepingcomputer.com/tutorials/how-to-start-windows-in-safe-mode/
• http://www.7tutorials.com/4-ways-boot-safe-mode-windows-10

WestEnd said

What plugin are you referring to?

The "plugin-container" not to be confused with NPAPI Plugins has existed in Firefox since 3.6.4.

http://kb.mozillazine.org/Plugin-container_and_out-of-process_plugins

Thanks for the clarification but no nearer a solution

Tried cor-el suggestions 1. I have no problem accessing web pages only transferring between some on high security (it appeaears, e.g bank) sites 2. Tried firewall (Windows Defender) change anyway - problem persisted 3. Tried Safe Mode approach but I'm on a wireless network and Safe Mode (with networking) doesn't connect to internet (or at least I can't make it) when connected wirelessly (have no wired connection to PC so can't check with wired/LAN network)

Solution still eludes me

Does it have effect if you disable Flash ("Ask to Activate") as that is the most likely candidate for plugin-container issues?

I have the same problem. If I go into task manager and delete the line for this PIA new piece of Firefox, everything works okay. But, this only started with the new build of Firefox and is so annoying it makes me want to switch back to Chrome. I was a huge Firefox supporter until this problem. Flash may be the cause, but with so many sites still using Flash, Mozilla should have figured out this new part of Firefox wasn't a good idea.