- the checkup page open a new page, one tab and same result
- idem for troubleshooting information
- restart in safe mode does nothing

- manual way => move the plist file, or any file related to firefox => same result after re-installation
- appZapper => same result

 - the menu for the video
 - the menu for images
 - the menu for link
 - ...

OS : OS X 10.9.2 Proc : 2,6 GHz Intel Core i7 Graphic : NVIDIA GeForce GT 650M 1024 Mo Ram : 8 Go 1600 MHz DDR3 Firefox 27.0.1 (tested with 28 and 26 and 25, same result) When launch firefox a window is opened, with a new tab and a blank page. None of the button works (i can enter my URL and click on "go to" button, or use enter keyboard, nothing's happened). None of the firefox webapp works (module page, troobleshooting page, clean page ....). If I go to help : - the checkup page open a new page, one tab and same result - idem for troubleshooting information - restart in safe mode does nothing I tried to clean the Firefox installation : - manual way => move the plist file, or any file related to firefox => same result after re-installation - appZapper => same result If I made a right click on the blank page, i have the complete menu (with all the option) for anything and not a contextual menu : - the menu for the video - the menu for images - the menu for link - ... I've tried everything, really, a lot of things. Please, help me, I need to use Firefox for my Job. All other browser are OK (chrome, safari, opera ...) : it's not a connection problem or what else. By curiosity, I tried Portable Firefox 4.0.1 who works like a charm ! But, if I let him upgrade to 27.0.1, its over and all do like I describe up.