Linux Mint cant boot because of missing partition

Uboatfreak · April 20, 2018

Hello!

I installed Linux Mint on my laptop as a dual boot with Windows 10, using the guide from here. Everything was fine, but I wanted to have a partition to use with both windows and Linux. So I tried to format /home from ext4 to fat 32, but I could not unmount it or format it because it said it was still in use. I got annoyed and just went into Windows and format it into ntfs from there. After that, Linux Mint would not boot, showing this error message . I went into a live usb session and formatted that partition as ext4, but linux mint still wont boot.

I went to see the etc/fstab file and compare it with the partition data shown by sudo blkid and this shows. The partition in question is nvme0n1p9. I read on the Ubuntu forums that I should edit the fstab file to be the same as what sudo blkid shows. Hoewever, I don't see anything in fstab that I can recognise as a partition. What do I do to fix this?

Wild Penquin · April 20, 2018

Hi Uboatfreak,

It seems that either 1) your fstab became corrupted (most likely) or 2) Mint uses some other scheme to mount partitions (very unlikely).

In any case, it is not surprising it broke. In my views you made at least three (understandable for a Linux beginner) mistakes:

First: always unmount filesystems before doing changes to them. That's why you could not do anything to your /home partition; it is always in use on a booted-up system. To make changes* to it, you need to boot into single-user (root/recovery) state, or use another OS (live Linux system would be easiest) to make the changes. Note: you can not just format it, which brings as to :

Second: You tried to format your partition from another OS (Windows). There is no way Linux (or any other OS) can keep track of that, and obviously it will fail (untill you fix things so that the OS is aware of what you made). This is a valid way to change the partition to use, but you need to know what you are doing (such as copy over any data from the old FS to the new one, and update /etc/fstab on the OS which is not running). There is already important data on a /home partition, even if you had not written any user-specific files / documents on it. The default users home directory, for example, which is created during the installation process.

There is a third error you made: You assumed you can use any file system. At least FAT32 should not be used for /home. Nor should NTFS (although, it just might be possible somehow). /home is a quite important system which will require all *nix features, like user, group ids and permission. FAT does not support these features, NTFS might support partly equivalent features. There are workarounds but none of them are easy and they are hacky and glued-on on to the FS (i.e. not recomended in any case!).

None of these explain why /etc/fstab got corrupted. If you made this via LInux Mints GUI instead of the command line, that could explain; the GUI program got confused about being unable to unmount nor format /home, and truncated the fstab it was in the process of preparing. But I'm just guessing here! EDIT: Also, this could be considered a bug in the GUI, if this really happened. GUIs should have safeguards for this kind of grave user errors!

Since you have already formatted your /home partition, I believe it is in this case easiest to re-install Mint. The alternative is, that you just restore /etc/fstab to the current installation. EDIT: But this can be a bit difficult, unless you have a copy of /etc/fstab, so re-install seems to be in order.

Also, the guide you linked is not available unless you register on that forum. It is best to stick to official documentation for installation in any case.

EDIT: *) Just realised "make changes" sounds a bit stupid here, but probably my thoughts came trough because of context. I actually meant is changes to the partition (such as the fs type, or resetting / formatting the whole fs etc...)

Edited April 20, 2018 by Wild Penquin

Uboatfreak · May 6, 2018

On 4/20/2018 at 3:09 PM, Wild Penquin said:

Hi Uboatfreak,

It seems that either 1) your fstab became corrupted (most likely) or 2) Mint uses some other scheme to mount partitions (very unlikely).

In any case, it is not surprising it broke. In my views you made at least three (understandable for a Linux beginner) mistakes:

First: always unmount filesystems before doing changes to them. That's why you could not do anything to your /home partition; it is always in use on a booted-up system. To make changes* to it, you need to boot into single-user (root/recovery) state, or use another OS (live Linux system would be easiest) to make the changes. Note: you can not just format it, which brings as to :

Second: You tried to format your partition from another OS (Windows). There is no way Linux (or any other OS) can keep track of that, and obviously it will fail (untill you fix things so that the OS is aware of what you made). This is a valid way to change the partition to use, but you need to know what you are doing (such as copy over any data from the old FS to the new one, and update /etc/fstab on the OS which is not running). There is already important data on a /home partition, even if you had not written any user-specific files / documents on it. The default users home directory, for example, which is created during the installation process.

There is a third error you made: You assumed you can use any file system. At least FAT32 should not be used for /home. Nor should NTFS (although, it just might be possible somehow). /home is a quite important system which will require all *nix features, like user, group ids and permission. FAT does not support these features, NTFS might support partly equivalent features. There are workarounds but none of them are easy and they are hacky and glued-on on to the FS (i.e. not recomended in any case!).

None of these explain why /etc/fstab got corrupted. If you made this via LInux Mints GUI instead of the command line, that could explain; the GUI program got confused about being unable to unmount nor format /home, and truncated the fstab it was in the process of preparing. But I'm just guessing here! EDIT: Also, this could be considered a bug in the GUI, if this really happened. GUIs should have safeguards for this kind of grave user errors!

Since you have already formatted your /home partition, I believe it is in this case easiest to re-install Mint. The alternative is, that you just restore /etc/fstab to the current installation. EDIT: But this can be a bit difficult, unless you have a copy of /etc/fstab, so re-install seems to be in order.

Also, the guide you linked is not available unless you register on that forum. It is best to stick to official documentation for installation in any case.

EDIT: *) Just realised "make changes" sounds a bit stupid here, but probably my thoughts came trough because of context. I actually meant is changes to the partition (such as the fs type, or resetting / formatting the whole fs etc...)

Hello Wild Penguin,

Sorry for the late response. I had some personal emergency the day after I posted this and just forgot about this for 2 weeks. Thank you very much for your informative response! Even if you just told me to reinstall Mint, you gave me a btter understanding of how Linux works. I will make sure to not make /home as a separate partition this time, I will make another partition to use jointly with Windows.

Have a nice day!