[SOLVED] Operating system not found / Dual boot

[tdarlic]

Hi guys

I've trying to solve this installation for hours now and cannot restore it.

I had Dell Inspirion with dual boot Linux Mint 18.3 and Win 10.
I just installed Linux Mint 21 over 18.3 using live USB. At the end of the installation I got an error complaining that the grub failed to install.
After rebooting I got Operating system not found error. My system was in Legacy boot.
I tried Boot repair program with several different options but none succeeded to make my machine boot.
This is the output of the program:
http://sprunge.us/ylXFXv

I remember vaguely having similar problem few years ago but managed to fix it with the same program.
My Windows installation on this machine is more important because of CAD program licence tied to this HW.
Any ideas?

[AndyMH]

My Windows installation on this machine is more important because of CAD program licence tied to this HW.

Did you take a backup before you started? LM21 overwrote the grub installed by LM18 which in turn overwrote the win bootloader, so the only way of booting win is via grub. Your win10 install iso should be able to repair the win boot but will lose mint.

I can't see anything wrong with the output from boot-repair, it re-installed grub to the drive with it pointing at sda7 - your / partition.

But the installer for LM21 is new or updated from that in LM20. There may be bugs we have yet to find.

I would wait to see what other informed suggestions you get, my suggestion, boot your mint install stick:

• run gparted, delete the logical partitions sd5, sda6, sda7. Note you haven't needed a swap partition since LM19, it will use a swap file by default.

• delete the extended partition, sda4.

• create a new primary partition, format ext4 in the space created. This will use up all of your primary partitions (max is 4) so you won't be able to create any more partitions.

• close gparted, run the installer.

• select the 'something else' option.

• the next screen shows your drives and partitions. Click on the partition you created, sda4, click the change button. Tell it to reformat ext4 and use it for / (this is on a drop-down menu).

• at the bottom of the screen it is asking where to put grub, select sda (you select the drive not a partition).

• continue the installation, it will complain about the absence of an EFI partition (one of the bugs in the new installer) - this can be ignored

Reboot, does it work?

I have tested LM21 with legacy boot with all four primary partitions used on a thinkpad T430 and it worked.

But as I said, wait for other opinion first.

[motoryzen]

What AndyMH explained I his first paragraph is just one of the dozen reasons why I never dual boot ( as in " install along side windows).

If there is something too important to lose or lose access to, it's always wiser to install the other operating system ( Mint in this case) into a separate physical storage drive AND ensure that windows drive isn't even connected at all when you boot into the Linux operating system.

Keep those two worlds separate, and you'll keep things and your data as well as your sanity intact.

[tdarlic]

Hi guys
First of all thanks for great advice, it was helpful and got me on the right track (with the help of colleague)
I managed to fix the boot by (sort of) following AndyMH advise after failing to fix anything with Linux Mint 21 live dist:

• Backed up entire disk by making image
• Run Win10 install/repair from USB media
• Run Win10 automatic boot repair (this failed to fix boot)
• Run

  Code: Select all

  bootrec /rebuildbcd
  bootrec /fixmbr
  bootrec /fixboot
  

• Run diskpart and made my windows partition active (At this point computer was booting Win10 sucessfully)
• Run Linux Mint 21 live dist again and use Gparted to delete all existing Linux partition and make one new ext4 partition
• Continue with installation of LM 21 choosing the newly created ext4 partition as \

After this the GRUB has taken over and it now lets me choose the OS to boot into.
I continue to use legacy boot.