Hi bernddasbrot, What OS do you use?

See analytical information in: Managing search engines

thank you

Please mark "Solved" the answer that really solve the problem, to help others with a similar problem.

I use Ubuntu 11.10 Linux

Managing search engines is not helpful, I already know it all.

try delete the specific plugin from:

C:\Program Files\Mozilla Firefox\searchplugins (for win os)

i do not known exactly the path in linux

EDIT: found something, Determining plugin directory on Linux , i do not known if this is helpful

thanks again

See:

• http://kb.mozillazine.org/Unable_to_search_or_add_new_engines