Start Firefox in Safe Mode {web Link} by holding down the <Shift>
(Mac=Options) key, and then starting Firefox. A small dialog should appear. Click Start In Safe Mode (not Refresh).

Is the problem still there?

Restarting the browser opens with a series of tabs for installing the extensions again.

Memory usage was roughly 3GB before restarting (and extensions still there btw). I looked at the page about:memory and found many closed pages using memory.

Using save mode i tried logging into twitter with tweetdeck, which is only a webpage that redirects to twitter and doesn´t use extensions. Unfortunately not working either.

This is bassically what happens all along, i have simple no clue anymore. I also removed any maintanance tools like ioBit and only use windows defender.

This is possibly caused by the multi-process feature that is enabled in the current Firefox release. Try to disable multi-process tabs in Firefox.

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

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

What security software do you have?

cor-el said

This is possibly caused by the multi-process feature that is enabled in the current Firefox release. Try to disable multi-process tabs in Firefox. You can disable multi-process tabs in Firefox by setting the related prefs to false on the about:config page.

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

What security software do you have?

I changed the second, the first was already disabled. Hope it works.

Until a week ago I used AVG but i switched to windows defender. AV´s are vulnerable because they run at the highest privilege level. They could for instance bypass the built in security without user interaction in the browser to verify if a site is safe.

I also used ioBit with Anti-malware but not anymore because it was mentioned somewhere on this forum to cause similar problems with logging in.

No, the list is empty. I disabled the multi-process tabs and the extensions. Memory is up and browser is running slow as before. Almost every control or button is getting slower.

I have lived with the problem now for a while, and hoped there would come up some solution. There is perhaps another thing that might cause it. In the first instance i accidently insalled the 32bit and used that for a couple of weeks. I tried to replace it but the problems were till there and it seems as if the old 32bit was not removed completely, however and some tools notice that i should use a 64bit version. Can you explain if this could be the problem and if there is a secure way to clean the old version from the system? I already removed the profile folders, etc. I have no idea what the registry has saved.

Let’s do a full clean re-install; Download Firefox For All languages And Systems {web link}

Save the file. Then Close Firefox.

Using your file browser, open the Programs Folder on your computer.

Windows: C:\Program Files C:\Program Files (x86)

Mac: Open the "Applications" folder. https://support.mozilla.org/en-US/kb/how-download-and-install-firefox-mac

Linux: Check your user manual. If you installed Firefox with the distro-based package manager, you should use the same way to uninstall it. See Install Firefox on Linux; https://support.mozilla.org/en-US/kb/install-firefox-linux

If you downloaded and installed the binary package from the Firefox download page, simply remove the folder Firefox in your home directory. http://www.mozilla.org/firefox#desktop ++++++++++++++++++++++++++++ Do Not remove the profiles folder.

Look for, and rename any Mozilla or Firefox program folders by adding .old to them. Do not rename the Mozilla Thunderbird folder if there is one.

After rebooting the computer, run a registry scanner if you have one. Then run the installer. If all goes well, remove the OLD folders when you are done. +++++++++++++++++++++++++++ If there is a problem, start your Computer in safe mode and try again.

http://encyclopedia2.thefreedictionary.com/Linux+Safe+Mode This shows how to Start all Computers in Safe Mode; Free Online Encyclopedia