More than one process is normal for the current Firefox. http://www.ghacks.net/2016/07/22/multi-process-firefox/

Multi-process Firefox is codenamed "e10s". https://wiki.mozilla.org/Firefox/multiprocess

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

Type about:config<enter> in the address bar. If a warning screen comes up, press the I Accept the Risk button. At the top of the screen is a search bar.

Thanks for your response, but the data usage is far too great. I'm going to have to stop using Mozilla Firefox.

HI, where are you getting the Data Usage information from ? As Task Manager is showing Ram and CPU Usage. Windows 10 has in Settings a Global Data Usage under Network & Internet --> Data Usage then can narrow that down by Clicking on the Link View Usage Details.

There should only be 1 entry for Firefox only. Though Plugin Container would be Firefox also I would guess. If there are 2 entries of Firefox please search for Programs & Features and check that you are not running 2 versions of Firefox.

If wanting to limit Windows itself from sending so much data you can uninstall all that you are not using in Settings and turn off all such as delete Maps and turn it off and use a online Map program, also turn off permissions and uninstall in the Start Menu by right click. You can then use a program like O&O Shutup10 https://www.oo-software.com/en/shutup10

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