1. Type about:config in browser and press enter.
2. Click on warning “I’ll be careful, I Promise” and type “newtabpage” (without quotes) in the search box
3. Double click on “browser.newtabpage.enabled” preference to change to “False”.
Additionally you may set "browser.newtab.url" to "about
lank" too if you tend to open multiple blank tabs & see that new tab page button.
