@oldfred

Sorry for not getting back earlier.

I am puzzled too, but have made some little progress. Here is what I did:
  • Booted from a Windows recovery usb stick.
  • In the command prompt, typed in "bootrec /fixmbr", "bootrec /fixboot", "bootrec /scanos", then followed these instructions.
  • At that point, I realized that in "EFI/Windows/Boot", the "BCD" file was missing but a backup file ("BCD.Backup.0001") had been made on the day when my computer stopped booting. So I copied the backup file to "BCD".

Following these steps, I could see the Windows and Ubuntu drives after entering the EFI bootloader (typing "F12" at startup). However, Windows wouldn't start and either stayed on the Dell screen indefinitely (with secure mode ON) or asked to be repaired (with secure mode OFF). Nevertheless, selecting the Ubuntu drive gave me access to the Grub, from which I could start Ubuntu normally (but the Windows entry wouldn't start).

Puzzlingly, when I restarted my computer, the Windows and Ubuntu options were not visible anymore in the EFI bootloader and the "EFI/Windows/Boot/BCD" was no longer present but had been backuped (this time as "BCD.Backup.0002"). After iterating the same repairs, I could again access Ubuntu (but not Windows). Here is the boot-repair report at this time.

Do you have any suggestion to move on (making the boot stable and restoring Windows)?

Thanks for your help,

Sebastien

Quote Originally Posted by oldfred View Post
@Sebastien
Not sure what to suggest. Some systems may auto restore or auto boot only Windows (see comments above). That is why Boot-Repair offers the renaming of files. But I thought Dell was one that worked.