Thank's for your reply but the solution proposed doesn't work.
When I go in LR - Edition - Préférence, when I desactivate the option, LR stops running.
And there is no update for the driver of my graphic card :
Informations relatives au processeur graphique :
ATI FirePro V (FireGL V) Graphics Adapter
I think I will have to change my graphic card....
Have you another solution to propose ?
Thank's for your help
Try the following:
Go to C:\Users\Your ursername\AppData\Roaming\Adobe\Lightroom\Preferences
There should be a file called Lightroom 6 Preferences.agprefs, open this file in a text editor.
Very close to the end there is a line that says useAutoBahn = true,
Change this to useAutoBahn = false,
Save and close the file, now try to start Lightroom.