New Tab Override (browser.newtab.url replacement) https://addons.mozilla.org/en-US/firefox/addon/new-tab-override/

With Firefox 41 (and higher), it's no longer possible to customize the page shown in a new tab via changing the preference browser.newtab.url in about.config. Because of the fact that hijackers abused the preference in the past, Mozilla decided to remove it (see bug 1118285). Fortunately, by removing it, Mozilla also introduced a new API to bring this functionality back to life as an add-on. This add-on allows the user to choose a certain page in a new tab.

After installing the extension, you need to use its Options page to set the desired new tab page (instead of using about:config).

Open the Add-ons page using either:

• Ctrl+Shift+a (Mac: Cmd+Shift+a)
• "3-bar" menu button (or Tools menu) > Add-ons

In the left column, click Extensions. Then on the right side, find New Tab Override and click its Options button. (See first screen shot attached.)

Depending on the height of your screen, you may need to scroll down to enter the desired address into the form. (See second screen shot attached.) For example:

• Page thumbnails (default) => about:newtab
• Blank tab => about:blank
• Built-in Firefox home page => about:home
• Any other page => full URL to the page

Then tab or click away from that form field and you can test using Ctrl+t.

Success?

Once you have it set the way you want, you can close the Add-ons page (or use the Back button to return to the Extensions list from that Options page).