After going into Airboot menu, I hidden some partition from ArcaOS. Then, I saw that win7 was unable to boot natively from its disk (win7 is on a different disk M.2 PCIe AHCI). I then removed hidden flags from under Airboot and could boot from bios into the win7 disk again....
But, what a surprise ! very sad surprise.
I have a 6TB GPT disk exclusively used under windows 7 with all my backups and all my archives and very important documents. This disk had only one 6TB partition but after changes I did under Airboot, this disk is now scrashed and I found on it 2 partitions ! One of 2TB and the rest as unassigned ! Airboot scrashed my GTP disk and all my datas ... it is very very dangerous and why did Airboot change my disk partitioning ?
How to recovery my disk and my datas ? ( user data integrity problems )
Regards
RD.