Hi Mark, you can easily choose a different page for your new tabs. Stopping Firefox from creating thumbnails is trickier, so I'll save that for someone else if you want to go that extra step.

Here's how you can change your new tab page:

(1) In a new tab, type or paste about:config in the address bar and press Enter. Click the button promising to be careful.

(2) In the search box above the list, type or paste newtab and pause while the list is filtered

(3) Double-click the browser.newtab.url preference and enter your preferred page:

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

Press Ctrl+t to open a new tab and verify that it worked. Fixed?

The forum software detected your Firefox as version 31. Is that an ESR release like 31.8.0esr from June 25th?

If not, you would want to update for security reasons. Mozilla discloses security flaws after each new release...

If you want to disable the thumbnails on the about:newtab page then create a new Boolean pref browser.pagethumbnails.capturing_disabled on the about:config page and set the value to true.

You can open the about:config page via the location/address bar. You can accept the warning and click "I'll be careful" to continue.

• http://kb.mozillazine.org/about:config

Delete the thumbnails folder in the Firefox profile folder to remove already stored web page thumbnails.

You can use this button to go to the current Firefox profile folder:

• Help > Troubleshooting Information > Profile Directory: Show Folder (Linux: Open Directory; Mac: Show in Finder)
• http://kb.mozillazine.org/Profile_folder_-_Firefox