Hi, updating to 52.9.0esr would be a good way if at all possible with your Mac Version.

• https://www.mozilla.org/firefox/organizations/all/

As well find a ad blocker or 2 that works. Finding one for ver 48 maybe hard.

• https://addons.mozilla.org/firefox/

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

Firefox 45.9.0esr will be the most up to date version with security fixes that will run on OS X 10.6, 10.7 and 10.8.

http://archive.mozilla.org/pub/firefox/releases/45.9.0esr/mac/ http://archive.mozilla.org/pub/firefox/releases/45.9.0esr/mac/en-US/

The Firefox 48.0.2 was released August 24, 2016 and is missing several security updates that the Firefox 45.9.0esr released on April 19, 2017 has.

sofedup said

Xfinity ad has infiltrated my computer. It shows up even when not connected to the internet.

Where does it show up, exactly? For example:

• Xfinity has taken over your Firefox home page -- the page that appears when Firefox starts up? See: How to set the home page
• Xfinity has taken over your Firefox new tab page -- the page that appears when you create a new tab (e.g., Command+t)? This can be caused by an extension so I'll suggest how to check those later in this message.
• Xfinity has embedded into your MacOS desktop? See Apple's help pages for how to change your desktop appearance.
• Somewhere else?

You can view, disable, and often remove unwanted or unknown extensions on the Add-ons page. Either:

• Command+Shift+a (Windows: Ctrl+Shift+a)
• "3-bar" menu button (or Tools menu) > Add-ons
• type or paste about:addons in the address bar and press Enter/Return

In the left column of the Add-ons page, click Extensions.

Then cast a critical eye over the list on the right side. Anything suspicious or that you just do not remember installing or why? If in doubt, disable (or remove). If legacy extensions can't be disabled or removed without quitting Firefox, there will be a link displayed for that purpose.

Any improvement?