How to fix GRUB (does not see windows 7 after formatting a disk with linux)?

Question

Windows

Formatted a disk with Linux, as a result, GRUB now writes unknown filesystem.
In parallel, there was Windows on another logical drive, all its files and the bootloader are in theory in order, how to enter it back?

Answer 1

Most likely, you have UEFI / EFI. I had this after installing Linux in parallel with Windows 7 on EFI. Grub just didn't "pick up" the right entry.
In Linux, do in the terminal, sweat as a root:
~# update-grub
~# reboot
If the desired item does not appear in the list of systems, we continue. Execute as root:
~# grub-probe --target=fs_uuid /boot/*/*/Microsoft/Boot/bootmgfw.efi the
output will be your Windows disk ID - write it down on paper
then execute (I use vim if you are not familiar with - any other console editor:
and at the very end, add a new line after all comments:
menuentry "Windows x86_64 UEFI-GPT" {
insmod part_gpt
insmod fat
search --fs-uuid --no-floppy --set=root YOUR_PAPER_ID
chainloader /EFI/Microsoft/Boot/bootmgfw.efi
}
Then run as root:
~# update-grub
~# reboot
Profit!