Score:0

Ubuntu

No Boot From Main Drive After Removing KDE Plasma

Trunk

11/19/22, 10:10 AM

I have (or, at least, had) Ubuntu 20.04 LTS on my main SSD drive with a similar SSD backup. I also have Ubuntu 21.04 on a USB so I could view Wayland.

To explore the KDE Plasma desktop environment, I followed this procedure to install it.

After I looked at KDE Plasma and found it less intuitive than Gnome, I found that simply rebooting forced me to select a desktop environment during the boot-up process. To get rid of this, I first tried to restore the state of my main SSD drive using Timeshift and a snapshot from a few hours before that was stored on my backup drive. This however did not seem to work as the desktop environment selection process was still displayed on start-up.

After that, I followed this procedure to remove KDE Plasma. But somewhere after stage 4, the whole screen just went black bar a message saying:

/dev/sda2: clean, 840296/15597568 files, 32058100/62383360 blocks

I saw a similar recent thread here but the "solution" there presupposes that the user can login and get on the CLI - which of course I can't as I am stuck on the black screen . . . I tried entering commands directly to the black screen but that has no effect.

I also tried to create a Ubuntu 20.04 LTS live USB drive using my Ubuntu 21.04 USB stick. But although this new USB drive has Ubuntu 20.04 files on it, it is not offered as a boot option of start-up and F12 . . .

Does anyone have any ideas on how to restore 20.04 LTS on my main SSD drive ?

EDIT

$ lsblk
NAME   MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
loop0    7:0    0     2G  1 loop /rofs
loop1    7:1    0  31.1M  1 loop /snap/snapd/11036
loop2    7:2    0  64.8M  1 loop /snap/gtk-common-themes/1514
loop3    7:3    0   219M  1 loop /snap/gnome-3-34-1804/66
loop4    7:4    0  55.5M  1 loop /snap/core18/1988
loop5    7:5    0    51M  1 loop /snap/snap-store/518
sda      8:0    0 238.5G  0 disk 
├─sda1   8:1    0   512M  0 part 
└─sda2   8:2    0   238G  0 part 
sdb      8:16   1  28.8G  0 disk 
├─sdb1   8:17   1    13G  0 part /media/ubuntu/usbdata
├─sdb2   8:18   1     1M  0 part 
├─sdb3   8:19   1   244M  0 part 
├─sdb4   8:20   1   2.7G  0 part /cdrom
└─sdb5   8:21   1    13G  0 part /media/ubuntu/writable1
sdc      8:32   0 238.5G  0 disk 
└─sdc1   8:33   0 238.5G  0 part /media/ubuntu/Inspiron-Backup
sr0     11:0    1  1024M  0 rom  
$ blkid
/dev/sda1: UUID="ECD2-CB1C" TYPE="vfat" PARTLABEL="EFI System Partition" PARTUUID="df09be0f-413b-445a-87ac-31723cc88b1c"
/dev/sda2: UUID="d06543c7-1ea7-4e4a-b1b2-7f09960d2111" TYPE="ext4" PARTUUID="c8df0139-5f2e-498d-889f-33b4f450deff"
/dev/sdb1: LABEL="usbdata" UUID="238C2AE754545054" TYPE="ntfs" PTTYPE="dos" PARTLABEL="primary" PARTUUID="81a44757-dfdb-4926-ab9c-59793c593509"
/dev/sdb3: LABEL_FATBOOT="usbboot" LABEL="usbboot" UUID="6CD1-EE08" TYPE="vfat" PARTLABEL="primary" PARTUUID="fc8d8c32-98ee-4cc3-8d71-50a8217a567e"
/dev/sdb4: UUID="2021-02-09-19-06-26-00" LABEL="Ubuntu 20.04.2.0 LTS amd64" TYPE="iso9660" PTUUID="38b1c112" PTTYPE="dos" PARTLABEL="primary" PARTUUID="641fcb46-1a0c-487d-a861-0348d144dad5"
$

0 + 12

kde

uninstall

boot

paladin

11/19/22, 10:24 AM

Are you able to restart and select another boot entry from the Grub menu?

Trunk

11/19/22, 10:26 AM

Yes, I can go into a live 21.04 USB - in fact I'm there now

Trunk

11/19/22, 11:31 AM

After removing the 21.04 USB and booting the PC with just the 20.04 USB, I can boot from the latter now. (Strange how the grub loader will not allow booting from 2 different versions of Ubuntu when they are on separate USBs . . . ) I tried the **boot-repair** procedure but this ended with an error and it did not boot from the SSD afterwards - just the same old blank screen and dev/sda2: clean etc.

paladin

11/19/22, 12:05 PM

Try to parse the UUID of the boot partition/volume instead of using a directory like `/dev/sdb1`.

Organic Marble

11/19/22, 1:29 PM

Can you provide more details on this: "forced me to select a desktop environment during the boot-up process." Normally one selects the desktop at login, so this sounds very off-nominal.

Trunk

11/19/22, 1:39 PM

@Organic Marble After trying to remove KDE Plasma by normal means, a reboot of the system brought up a window offering a choice of desktop environment. Unlike your experience, this choice of DE window was never visibly present before KDE Plasma was installed. After installing KDE, the boot would not proceed until a choice of DE was made by me. I got tired of this unnecessary step and saw no way to set a default for Gnome DE. So I looked through the web for a procedure to completely remove KDE Plasma and applied its instructions - till my system crashed.

Organic Marble

11/19/22, 1:43 PM

Is it possible that the selection was for the display manager? Not the desktop? I think KDE uses sddm for a display manager, most others use gdm or lightdm. You may have ended up with a display manager that you don't want.

Trunk

11/19/22, 1:46 PM

I don't think so. During the KDE Plasma installation, the display managers you mentioned were listed and oen had to choose sddm for installation. But as far as I can recall. the boot-up process offered things like Plasma, Gnome and Unity, all within a sky-blue framed window.

Organic Marble

11/19/22, 1:47 PM

Can you boot into recovery mode from the grub menu?

Trunk

11/19/22, 2:18 PM

I can only boot in recovery mode from the USB installation - see images added to my opening post.

Trunk

11/19/22, 2:57 PM

This thread https://askubuntu.com/questions/1280045/how-to-delete-kde-plasma-installed-using-tasksel-in-ubuntu-20-04-completely worries me. It suggests that a new system install may be the only cure for these ills.

Trunk

11/19/22, 4:21 PM

Not much help available here in getting out of this mess. Only thing contributors are interested in is in exploring curious behavior of Ubuntu and KDE. Does everyone here work for KDE ? Maybe we should create a new **Ubuntu - Support Only** forum . . .

Elon Musk

I sit in a Tesla and translated this thread with Ai:

EN: No Boot From Main Drive After Removing KDE Plasma

TH: ไม่มีการบูตจากไดรฟ์หลักหลังจากลบ KDE Plasma

RO: Fără pornire de pe unitatea principală după eliminarea KDE Plasma

RU: Нет загрузки с основного диска после удаления KDE Plasma

VI: Không khởi động từ ổ đĩa chính sau khi xóa KDE Plasma

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