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I installed Windows 10 on a separate disc, while my other (original) disc had Ubuntu 20.04. I don't recall, whether my original Ubuntu disc (shown in picture) already had 3 rather than 2 partitions, but now it shows:

enter image description here

Where the highlighted partition seems to report as "Windows 10" in GRUB.

Is this something added by installing Windows 10 on a second SSD? Or what is it? Can I delete it?

update-grub reports:

sudo update-grub
Sourcing file `/etc/default/grub'
Sourcing file `/etc/default/grub.d/init-select.cfg'
Generating grub configuration file ...
Found linux image: /boot/vmlinuz-5.15.0-48-generic
Found initrd image: /boot/initrd.img-5.15.0-48-generic
Found linux image: /boot/vmlinuz-5.15.0-46-generic
Found initrd image: /boot/initrd.img-5.15.0-46-generic
Found linux image: /boot/vmlinuz-5.13.0-52-generic
Found initrd image: /boot/initrd.img-5.13.0-52-generic
Found memtest86+ image: /boot/memtest86+.elf
Found memtest86+ image: /boot/memtest86+.bin
Found Windows 10 on /dev/sda1

Contents look like:

enter image description here

I speculate this is related to:

https://askubuntu.com/a/158319/684850

This https://linuxconfig.org/how-to-install-ubuntu-22-04-alongside-windows-10 suggests that it might be a result from dual booting.

Potential solutions:

Could I clone the Ubuntu on this disc to another disc w/o the Windows partition?

mavavilj
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  • @user68186 Based on: https://askubuntu.com/questions/1111045/how-to-check-if-ubuntu-has-booted-in-uefi-mode my system reports "bios" i.e. it's not with EFI. OTOH /boot does contain an efi folder. Does this suggest that installing Windows 10 on another disc modified my Ubuntu disc also? – mavavilj Sep 28 '22 at 19:40
  • I also tried to delete this partition earlier and it broke GRUB so that even Ubuntu wasn't found anymore. This took 3-4 hours to repair. – mavavilj Sep 28 '22 at 21:05
  • @user68186 But I have no Windows anymore. It was also installed on a physically separate SSD. I don't understand why there's this partition on my Ubuntu disc. Unless it's from something I did years ago, and I haven't been paying attention to it. – mavavilj Sep 28 '22 at 21:09

1 Answers1

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That is the recovery partition created by windows 10 during installation. When you're creating new partition on an MBR disk, Windows will create a system reserved partition, and if it is a GPT disk, then Windows will create a recovery partition and an EFI system partition without a drive letter. The recovery partition on Windows 10 consumes about 450MB which would fit in that 537MB partition you have there. It is safe to delete if you don't care about recovering your Windows installation and want to free up some space.

This is how to delete the recovery partition in Windows. Use diskpart to remove it as shown in the link. You could also use disks in Ubuntu, which would accomplish the same thing.

G_Style
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  • But I also read that partitions must be adjacent in order to merge free space back to reserved space. I'd have sda1 as free, sda2 as non-free, sda3 as target of merge. – mavavilj Sep 28 '22 at 21:25
  • Does this imply however that I have had a Windows partition on this particular disc? Or did it create that partition on that disc, even when Windows was installed on another disc? – mavavilj Sep 28 '22 at 21:35
  • I'm also confused about, why these partitions don't have labels. – mavavilj Sep 29 '22 at 09:01
  • Yes, partitions do need to be adjacent to reclaim free space. You can use a program like gparted to move your partitions around to do so, once the recovery partition is removed. This does not imply you have your windows partition on that disk, as I do not know how you installed Windows. As I said before, Windows did create that partition on that disk. Partitions do not require a label by design. – G_Style Sep 29 '22 at 14:28
  • So the community can benefit, please mark as the answer if this helps. – G_Style Sep 30 '22 at 17:21
  • I've not deleted my partition, because I'm afraid it will break something. – mavavilj Feb 21 '23 at 10:54
  • I've reinstalled Windows on sdb (https://askubuntu.com/questions/1455976/grub-works-differently-depending-on-whether-one-boots-from-sda-or-sdb), and sda still has this W95 partition. At this point I don't know if the partition is related to Windows 10 on sdb in any way. – mavavilj Feb 22 '23 at 07:48