Hi, I am running FF 43.0.2 64Bit on Window 10 Version 1511 (OS Build 10586.36). The main issue are: 1. Search Bar issue: All over sudden the search bar didn't work anymore. I am able to insert the search request but the enter of the keyboard was "ignored" somehow, so the search never starts. 2. Mozilla Firefox Start Page At the same time/session the webpage opens and I can insert there also my search request but again the enter of the keyboard was "ignored" somehow, so the search never starts. 3. Add-ons: I had ad-dons installed and they worked without an issue. As soon the problems mentioned in point 1. and 2. appeared I tested if it was related to the add-on but none of them was responsible for the problems. I ran FF in safe mode and the problems mentioned in 1. and 2 where not present but as soon I started in normal mode they re-appeared sporadically. To fix the issue I refreshed FF and tried to install my add-ons. The installation process is done and a restart of FF is request. After the restart FF is not showing any Add-ons installed. Before the refresh the updates for add-ons failed too. I completely uninstalled FF, deleted all related folders in: C:\Program Files (x86) C:\Program Files C:\Users\*******\AppData\Local C:\Users\*******\AppData\LocalLow C:\Users\*******\AppData\Roaming I reinstalled FF 43.0.2 64 Bit facing an even bigger problem. Now I don't have any add-ons installed due to the fresh install, but I can't install any add-on at all !?!?! The installation progress meter shows the installation and FF request a restart but after the restart no add-ons. I started FF as administrator and and repeated all steps as administrator but nothing worked. I followed many help and fixes from the FF-support forums but nothing is solving my issue. Many thanks in advance for the support. Muka