What happens now when you search from the address bar? For example, do you get results on a different site? Does Firefox report that a site couldn't be found?

If you get no response:

There is a problem if you do not enable ANY suggestions from the four possible categories:

• Bookmarks
• History
• Open tabs
• Search engine suggestions

In that case, the address bar stops working normally. Make sure you have at least one kind of suggestion enabled. See the "How can I control what results the address bar shows me?" section of the following article: Address bar autocomplete suggestions in Firefox.

Does that help?

Sorry. That doesn't fix it. I didn't change anything in my settings to make it change its behavior, so I don't understand what's wrong. If I type anything in the address bar, Firefox is assuming I'm trying to get to a site, and yields this message instead of searching a search site: "Hmm. That address doesn’t look right. Please check that the URL is correct and try again."

My settings are to "Use the address bar for search and navigation" and "Provide search suggestions" through Google.

Gotcha, the bar responds, but doesn't search. Please check the following preference:

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

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

(3) If the keyword.enabled preference is bolded and has a status of "modified" or "user set", and a value of false, double-click it to restore the default value of true

If that preference has a status of locked then:

Some users in a managed environment have reported that their IT locked out address bar searching. For example: Search from navigation bar doesn't work. You might check with your IT on whether that is your company's setup as well.