I have a problem with boot system with 3 OS(Windows 10, Windows 7, Linux).
Before, when booting the system (dsa disk), the windows 10 boot system could select between that 3 OS without any problem.
But, one day, when selecting the Linux OS in the windows boot system (where GRUB had installed) the GRUB failed and to fix it I have done:
sudo mount / dev / sda3 / mnt (sda3 is my linux partition) sudo grub-install --root-directory = / mnt / dev / sda
Now, when I turn on the PC, GRUB load first (with errors), instead of the windows boot system, but I do not want this.
How can I undo my last change (grub-install) so rescue previous boot system (from windows 10)?