Thanks @Sebastian-Roth it worked!
On the other hand, as you expected, I had to boot via the live usb grub-repair, then I ran the 2 commands
grub-install /dev/sda
then
update-grub
I also modified the /etc/fstab which was not correct anymore…
On the other hand, I have another problem that I can’t solve. I made some updates on my system (sda5 partition) and I want to capture it again to deploy it. Why do I get this error, knowing that it is an old linux system on the workstation:

Why does Fog check this sda2 file system? And how can I get away with my capture?
Thanks a lot for your help!