Firefox doesn't disable anti-virus applications. But it will disable silly, little Add-ons that do little to provide real security, when those add-ons aren't signed. And those types of add-ons usually duplicate features that are already built into Firefox.

There is an override that you can enable to allow unsigned add-ons to be enabled.

https://support.mozilla.org/en-US/kb/add-on-signing-in-firefox#w_what-can-i-do-if-firefox-disables-an-installed-unsigned-add-on

You can override this setting by changing the xpinstall.signatures.required preference to false in the Firefox Configuration Editor (about:config typed in the URL bar). Support is not available for any changes made with the Configuration Editor so please do this at your own risk.

Thanks!

Like I said, non-geek user here. I wish they would be more explicit because to me adding Kapersky to my computer made it an "add on"

Remember the core paid for Anti virus will continue to work as long as you keep it up to date and paid for.

There will be another Firefox version in about another two weeks, that will probably be the last version that allows unsigned addons.

It is probably also worth noting that you appear to be using Windows 10 that comes with built in Anti Virus and a Firewall, so there may be very little benefit in paying for a separate AV.

• A simple guide: http://windows.microsoft.com/en-gb/windows-10/getstarted-protect-your-pc
• Some techie details
  Windows 10 security overview
  https://technet.microsoft.com/en-us/library/mt601297%28v=vs.85%29.aspx?f=255&MSPPError=-2147217396

Other readers of the thread: Note if you use Windows Vista or Windows 7 you may add the free Windows MSE which includes Anti Virus.

• For description and download see http://windows.microsoft.com/en-US/windows/security-essentials-download