unable to restart crashed system

[mj2579]

PS. I've just noticed a "247 GB Volume" on the desktop. A double-click shows that all my files on the hard drive are intact. I've got a blank memory-stick that I can copy files to (if I can work out how to do that). After that, I will need help getting the new Mint installed on the hard drive without wiping it.
TIA.

[SMG]

I opened a terminal window and keyed in 'sudo fdisk -l'
The reply indicated three disk drives:
- /dev/nvme0n1p1 ... 512M EFI system
- /dev/vnme0n1p2 ... 230.1G Linux filesystem
- /dev/vnme0n1p3 ... 7.9G Linux swap

p1 must be the memory stick I booted from, p2 must be my hard drive (which I think is not partitioned), and I don't know what p3 is.

This is actually one disk (your hard drive which is an nvme drive) with its three partitions. The first partition is your boot partition (you are booting EFI). The second partition is your Mint installations (your root partition and all your files). The third partition is your swap partition.

I don't see a "/dev/sdXX", so I have no idea how to progress from here. What I would like to do is to use the current access (by memory-stick boot) to see and save hard drive content before trying to re-install Mint on the hard drive. Assuming the hard drive content is still there. Then I would like to install the new Mint version without wiping the hard drive. As you can no doubt tell, I am not at all familiar with Linux Terminal, and have rarely used it.

You were able to access the hard drive to run sudo fdisk -l, so you should be able to see the drive using the Files app (File Manager) and GParted.

PS. I've just noticed a "247 GB Volume" on the desktop. A double-click shows that all my files on the hard drive are intact. I've got a blank memory-stick that I can copy files to (if I can work out how to do that). After that, I will need help getting the new Mint installed on the hard drive without wiping it.
TIA.

I do not recall on which version of Mint Timeshift snapshots became available. You may not have had it, but if you did, you could open the Timeshift app on the live session to restore to a snapshot and maybe get your LM18 working again.

[mj2579]

Yes I've opened File Manager and am now copying data from hard drive to blank memory stick.

I gave no idea how to use Timeshift. I wonder whether it is worth trying that, or whether to continue with Mint 20. If I did get Mint 18 reinstated, presumably(?) it would be a simple matter to upgrade to Mint 20, and I definitely wouldn't lose anyhthing that way. If I install Mint 20 now, maybe I lose data, but I can restore that from the backup memory stick, but would I also risk losing installed software and have to reinstall it all?

[SMG]

I gave no idea how to use Timeshift. I wonder whether it is worth trying that, or whether to continue with Mint 20.

It is not something you can do after the fact. You would have created the snapshot before all this happened. I am not positive, but I think Timeshift did not become available until LM18.3 which would mean it was not available for you.

If I did get Mint 18 reinstated, presumably(?) it would be a simple matter to upgrade to Mint 20, and I definitely wouldn't lose anyhthing that way. If I install Mint 20 now, maybe I lose data, but I can restore that from the backup memory stick, but would I also risk losing installed software and have to reinstall it all?

There is no simple upgrade from LM18.1 to LM20. You would have to first update to LM18.3 then do the manual update to LM19. Then update to LM19.3. Then do the manual update to LM20. You are much better off making a clean install of LM20.

You should be able to back up all your personal data using File Manager presuming you have enough memory stick space to do it.

You will have to reinstall software. Most of the software would need newer versions and need to be reinstalled anyway. However, I would think there would be a way to get a list of all the software you have installed. You might have to create a new thread asking for that information. I do know how that might be done as I really do not have experience accessing that information on an LM18.1 install using the live session.

[mj2579]

Apologies for the dead thread, I've been away the last 7 weeks. I think I've now stuffed everything up. I backed up all my files to memory stick, so I still have those. I the installed Mint 20, and it offered an option of installing Mint 20 alongside Mint 18, and this was the only option that said it would preserve my programs, files, etc, so I chose that. Now I can run under Mint 20, but it seems to be completely separated from the Mint 18 stuff, so (a) I have effectively lost all the files off the computer anyway if I can't see them (Mint 18 is bust), and (b) I can't install them under Mint 20 because all the disk space is with Mint 18 and I have little spare space under Mint 20.
- - -
I gave up on all that, and I'm re-installing Mint 20 as a clean install. Hopefully I will be able to restore all my files, reinstall software (i don't think I had much), etc.

I'll mark this thread closed, but if anyone on the Linux team can use any if this to see how things can be made easier, that might help others???

[SMG]

I the installed Mint 20, and it offered an option of installing Mint 20 alongside Mint 18, and this was the only option that said it would preserve my programs, files, etc, so I chose that. Now I can run under Mint 20, but it seems to be completely separated from the Mint 18 stuff, so (a) I have effectively lost all the files off the computer anyway if I can't see them (Mint 18 is bust), and (b) I can't install them under Mint 20 because all the disk space is with Mint 18 and I have little spare space under Mint 20.

The underlying code of the operating systems are different enough between LM18 and LM20 that you would have to reinstall programs anyhow. There is no way to take programs from LM18 and use them on LM20. The installer told you they were being preserved because the installer was not overwriting them. That is how they were preserved.

I'll mark this thread closed, but if anyone on the Linux team can use any if this to see how things can be made easier, that might help others???

This is a forum where Mint users help other Mint users. I'm not sure what you want the Linux team to "make easier". When each release comes out, there are instructions on the Mint blog about how to upgrade. They make it as easy as they can, but one needs a running system to be able to do it. With LM20 you have Timeshift available to you. That is a good way to create a snapshot of your working system files so if something happens, you can restore your system to that snapshot using Timeshift.

To mark the thread closed, you will need to go to your very first post in this thread and edit the title of that post.