Sorry, that preference was deprecated Firefox 48 & later versions.

Might be awhile before someone comes with a "fix".

Thanks anyway. Maybe it's time for me to switch to Chrome.

Just some clarification for any other readers of this thread.

You can certainly remove Google as a search engine on Firefox IF that is what you are trying to do

You may choose what Seaarch engine Firefox uses by defaukt. There are built in choices, You may add or delete other search engines. The change in Firefox48 is not preventing that. You may also choose whether or not to display search engine suggestions.

For more details of the many choices please see

• Add or remove a search engine in Firefox
• Manage Firefox search settings
• Search the web from the address bar
  • including turning off domain guessing
• Remove websites from the address bar suggestions
• Settings for privacy, browsing history and do-not-track

Just had the same problem. I found two possible solutions:

1. https://userstyles.org/styles/122394/url-bar-tweaks-remove-visit-search-scroll-bar

Basicely it uses the addon stylish to edit the task bar suggestions ui and 'hide' the first element in the list. Not particuarly elegant but it works. The site offers a few option to try out, see what looks best to you.

2. Addon Classic Theme Restorer offers a similar implementation. Although it implements many more UI changes, you'll have to see if it is for you.

Cheers!

Thanks. It worked.