I can no longer start my computer

[GreyGeek]

Thank you very much GreyGeek for your explanations!
When I prepare the new installation of Kubuntu 16.04, I don't have the possibility to choose the filesystem. Where we want to install Kubuntu 16.04, there is already Kubuntu 16.04 and for the computer there is no question such as "Which filesystem?". I can choose the filesystem only if I delete the existing Kubuntu 16.04 or if I install the new one on a virgin part of the HDD. Please, should I delete my existing Kubuntu 16.04 or do something else?

There is only 3 years left till EOL of 16.04 and 18.04 is good for FIVE more years. It will be released on 4/26, nine days from now. I would install the latest daily beta and then let it continue updating. During the install, when you come to the section where your HD is partitioned and formatted, the default choice is EXT4. That is displayed in what is called a "drop down combo box". If you click on it the options will pop up and one is Btrfs. Choose it and continue with the process. What else you do depends on if you are dual booting, using a swap partition or swap file, etc...

My plan is to find out when KDE Neon, which I use, is updating to 18.04 and jump to it with a fresh install.

[SpecialEd]

>>>>>
My plan is to find out when KDE Neon, which I use, is updating to 18.04 and jump to it with a fresh install.

My plan is to wait a week until you've worked out the kinks and do the same.

[GreyGeek]

My plan is to wait a week until you've worked out the kinks and do the same.

Great plan!

[nicrnicr]

The system crashed during the installation of Kubuntu on a btrfs filesystem.
Now, when I turn on the computer I get

error: unknown filesystem.
Entering rescue mode...
grub rescue>

Thank you very much for the information about Kubuntu 18.04! But: I don't like to update, because each time the computer gets slower and sometime I may have a problem with a software.

[GreyGeek]

The system crashed during the installation of Kubuntu on a btrfs filesystem.
Now, when I turn on the computer I get

error: unknown filesystem.
Entering rescue mode...
grub rescue>

Thank you very much for the information about Kubuntu 18.04! But: I don't like to update, because each time the computer gets slower and sometime I may have a problem with a software.

I don’t like to update either, a clean install always works better, IMO.

You should download a fresh copy of the 18.04 ISO, checksum it and burn a LiveUSB. After booting it use the grub menu option that checks the LiveUSB.
If it checks out then install it. Do use the Btrfs option. You’ll never regret it


Sent from my iPhone using Tapatalk

[nicrnicr]

Thank you GreyGeek for your answer.
I have a Windows and a Kubuntu 14.04 that I don't want to erase on my computer. Therefore I'm searching a solution to

error: unknown filesystem.
Entering rescue mode...
grub rescue>

I choose the manual installation because the automatical ones seemed inapropriate. I had to formate again the Kubuntu 16.04 part because the installation could not go with the existing ext4. I choose sda as Bootloader and / as mount point.

[nicrnicr]

I'm now using Boot repair.

[nicrnicr]

Hello everybody,

I couldn't login Skype. I deleted it and installed it again. Then I couldn't use Office. I deleted it and installed it again. Then I couldn't shut down, therefore I wrote shutdown in the terminal. Then I couldn't access to Kubuntu 16.04. I tried to install it again. Now I cannot even access to the grub (or ifo).

So the lesson that I learned is that I have to ask anything I do, if I want to avoid problems. The report of Boot Repair is http://paste.ubuntu.com/p/y68Mbf7Rgv/
Please, could you write me, what I have to do?

[GreyGeek]

Thank you GreyGeek for your answer.
I have a Windows and a Kubuntu 14.04 that I don't want to erase on my computer. Therefore I'm searching a solution to

error: unknown filesystem.
Entering rescue mode...
grub rescue>

I choose the manual installation because the automatical ones seemed inapropriate. I had to formate again the Kubuntu 16.04 part because the installation could not go with the existing ext4. I choose sda as Bootloader and / as mount point.

Using boot repair is currently you best option.
You say you have (had?) 14.04 and don't want to erase it, but wanted to install 16.04? So, you plan was to have three partitions Win10, K14.04 and K16.04. To do that you would have to shrink either/or/both Win10 and K14.04 to create enough room, 50+GB to install K16.04. BTW, 14.04 has an End Of Live of April, 2019. 16.04's EOL is April, 2021, and 18.04's EOL is April, 2023.

Did you inadvertently install 16.04 on top of 14.04? Or, were you attempting to create a new partition out of either the Win10 or 14.04 partitions?

While doing a fresh install on an available partition (clean or containing an existing OS) reformatting is usually necessary. Some well experienced users partition root (/) and home (/home) on separate partitions but most, with casual experience, do not have that ability. The ONLY way you can install Btrfs as the root filesystem is to use the manual install and format the partition using Btrfs. The Btrfs install will automatically create a "@" root subvolume and a "@home" home subvolume on the installation partition. Subvolumes are Btrfs's form of directories that are created by Btrfs create commands, not the usual mkdir command which, still works but creates traditional directories, not subvolumes. The number one advantage of Btrfs is the ability to make a backup snapshot of your system in a few seconds, and to restore a broken system (broken or otherwise) to a previously made snapshot in under five minutes.

[nicrnicr]

Thank you GreyGeek for your answer.

There are now in order Windows, approx. 50 free GB, the place of the old Kubuntu 16.04 which I formated btrfs, Kubuntu 14,04,, maybe free further GB (but I couldn't see it) and of course a few small parts such as swap which are among the other big parts. There are, but I cannot access them.
I tried to install manually Kubuntu 16.04 exactly on the place of the old one.

[GreyGeek]

...
I tried to install manually Kubuntu 16.04 exactly on the place of the old one.

When you say you “can’t access them”, I assume you mean that after the grub menu comes up and you select one of the three, regardless of which one, it fails to start.

Even though it displays a menu it appears to me that grub is borked.
https://www.tecmint.com/rescue-repai...der-in-ubuntu/

[nicrnicr]

Thank you GreyGeek for your answer.

No. There is no longer any grub.

[nicrnicr]

. . . . .

[GreyGeek]

Thank you GreyGeek for your answer.

No. There is no longer any grub.

I suspect that there is no OS on your Linux on your HD, either. Windows may be gone as well.
If so, that's the best news of all, because it gives you the opportunity to move completely to Kubuntu without having to bother with dual booting Win10.

Just boot to your LiveUSB and at the section which allows you to partition your HD delete all existing partitions and create one partition. Use Btrfs as the filesystem on that one partition and check the format checkbox. Then continue. If your Internet connection isn't very fast (<30Mpbs) then uncheck the box that says to install updates. You can do that later with the apt program. Do NOT choose compression on your home account. If that borks I doubt that you would be able to recover from it. After the install is compete and you've booted into your home account do the following
1) Open a Konsole
2) Issue
sudo -i
and enter your home account password.
3) Issue
mount /dev/sda1 /mnt
That assumes that you created a partition which will be sda1 and didn't install directly to sda.
4) Issue
mkdir /mnt/snapshots
5) Issue
btrfs su snapshot -r /mnt/@ /mnt/snapshots/@firstinstall
btrfs su snapshot -r /mnt/@home /mnt/snapshots/@homefirstinstall
sync
sync
6) Issue
umount /mnt
exit
exit

You've now made a complete backup of your initial installation. If you bork anything you can recover it easily

Rolling back:

1) Open a Konsole and issue
"sudo -i"

2) Mount sda1 on /mnt
mount /dev/sda1 /mnt

3) Move @ to @_old
mv /mnt/@ /mnt/@_old
sync

4) Move @home to @home_old
mv /mnt/@home /mnt/@home_old
sync

5) Copy /mnt/snapshot/@firstinstall to /mnt/@
btrfs subvol snapshot /mnt/snapshots/@firstinstall /mnt/@
sync

6)Copy /mnt/snapshots/@homefirstinstall to /mnt/@home
btrfs subvol snapshot /mnt/snapshots/@homefirstinstall /mnt/@home
sync

7) Delete @_old and @home_old
btrfs subvol delete -c /mnt/@_old
btrfs subvol delete -c /mnt/@home_old

8) Exit root and Konsole
exit
"exit

9) Reboot

[nicrnicr]

Dear GreyGeek,

Thanks to you I could repair the grub and I have access to Windows and Kubuntu 14.04 again.

Now, I would like to install Kubuntu 16.04 (I prefer older systems to new ones, among other things because they work better, because the older a computer the less adapted is a newest system, because I don't have to prepare a new USB-system). Furthermore I would still have the possibility to install Kubuntu 18.04 on Kubuntu 14.04 later if I need/want. I can do it only manually.

If I repeat what I did: choosing the btfrs part, choosing sda as Bootloader and / as mount point, it should crash a second time.
Please, do you know what I should do in order that it work?
I'm struggling since too lang to enclose a picture of my partition...