See if this link helps - http://kb.mozillazine.org/Unable_to_search_or_add_new_engines

Thanks but that did not solve the problem. It did prevent me from logging in though until I reverted back to the right file name.

I have uninstalled and reinstall FF4 but the problem still exits.

Any other ideas please?

Hi Tony,

Any more ideas please? If not then how do I go back to my previous version of FF please. I did not have that problem before I upgraded.

I have removed FF4 and reinstalled FF3.6.16 and the search bar works fine - like it always did.

Shame I cannot use FF4. Would you please let me know when a solution to this problem can be found? BTW I do have Copernic Desktop Search installed. When I installed FF4 I did get a message that the Copernic add-in was not compatible. Could this be a problem?

Tried again. I should have read the full instructions the first time although it was a bit confusing. Deleting the formhistory files from my profile solved the problem. Thanks.