In the patch view, dimmer is missing, also new fixture I have.
I have a fixturelibrary installer from juni and it works

Ok !! Thanks a lot guys !
EDIT: I had to leave so I edit my thanks.
So, for summarized for posterity and other newbie like me

I finally erase the hard disk with the recovery creator v7.1 and use the updater for 7.4.
The updater exe file is to run on the console with a normal USB key.
The Recovery exe file is to run on a windows OS and it will need a free USB key formatted. Maybe it need to be format with RMPrepUSB software available on the web and independent from Avolites. In this case one should uncheck the format option during the Recovery execution.
With version 7.1 I have a "dingle not found" error message, I just ignore it and upgrade to 7.4 (it will need and activation for Avolites. It need some photos and serial number and in my case a few hours).
The (...)FixtureLibrary.exe file for personalities have trouble today and some fixture are not installed (like the "dimmer" fixture).
Thank you
Niclights and
Gregory for your quick help along this stressing 24 hours for me. I owe you big time! My show tomorrow is saved

and sorry for my pore English I hope it did not give you too bothered.