Try using the search bar instead as a test. If that works it is likely to be a known but yet unfixed issue. (I will tag this thread with bug118040).

Current Suggested fix. (Bug 1180419 related)

1. Edit as a first step try downloading and using the addon places maintenance, that does sometimes fix the corruption. It may not work but is a quick and easy step, and may preserve usable History and fix the address bar so is well worth trying.
   • https://addons.mozilla.org/firefox/addon/places-maintenance/
   • If that works no need to think about step two, or the rest of this post.
2. Rename the file places.sqlite as explained in this recently revised article.
   Unfortunately you lose your browsing History when you do that but the Firefox address bar will work again.
   • Can't add, change or save bookmarks - How to fix_fix-the-bookmarks-file

For more detail please see

• Firefox won't load sites from URL ... /questions/1071439

Please post back to say how you get on. I know this is rather an unlikely sounding fix. I know if it is this particular problem standard reinstalls, even standard clean reinstalls do not fix it. The Firefox refresh also does not fix this.

There is a bug fix in one of the pre-release versions already. I am not yet sure when a bug fix will make it in to the Release and be available to everyone.

Update

Just checking bug progress and the fix is approved for the Beta channel and the Developer edition Channel so should be available there any day now. It is looking as if the fix in the Release channel may wait until Fx42, although I did notice a staff member comment suggesting we may get an early fix that I took to mean in Fx39 within a few days.

Beta channel is the most stable. The Developer edition is easier to install and use, because it installs as a separate additional browser with its own profile.

• Beta: Downloads from https://www.mozilla.org/firefox/channel/#beta
• Developer Edition (was Aurora) https://www.mozilla.org/en-US/firefox/channel/#developer

If we need to wait for Firefox 42 for a bug fix, then assuming the bug fix is in Developer soon then it may be worth using that for a few weeks.

• Also see Get help with Firefox Developer Edition
  Recover lost bookmarks on Firefox Developer Edition

If you wish to follow the bug progress. You can look at

• Bug 1180419 - Cannot load URLs from the address bar if places.sqlite is corrupt
  • It is not somewhere you should normally comment, unless for instance you are replying to an appeal for information. Note etiquette
  • The etiquette link also mentions following by CC. If you register then click on the save details button you will receive emails for bug updates.
  • There is also an option to vote for bugs ( See [https://bugzilla.mozilla.org/page.cgi?id=voting.html voting)