no boot anymore

[nicrnicr]

Thank you oshunluvr for you answer :-)
I made what you advised me.
For

cat /var/log/Xorg.0.log

The answer is no path or file like this
and for

cat ~/.xsession-errors

the answer is no such command.

I also looked in the internet for a solution to this problem. There are many such cases, there are many possible solutions and there are many people which solved this by a new installation... I will begin to apply the series of solution and write here how it's going on.
Thanks all for reading!

[nicrnicr]

Hi,
Someone wrote that it worked again after he updated and upgraded. I did it and received:

Failure after work on:
/var/cache/apt/archives/kio-extras-4%3a16.04-3-Oubuntu1~ubuntu16.04~ppa61_amd64.deb
/var/cache/apt/archives/kio-extras-datas-data-4%3a16.04-3-Oubuntu1~ubuntu16.04~ppa61_amd64_all.deb
E:Sub-process/usr/dpkg returned an error code (1)

as an answer. This has something to do with the many installations that I*did as I had the aim to install Kolourpaint.

Furthermore, it didn't work for me.

I also read that I should
- change the name of .cache or delete it as .config .local and it could work.

- write "sudo apt-get install --reinstall sddm; sudo dpkg-reconfigure sddm
After reboot I my had graphical login, but my user was missing (UID=501).
Fixing required creation of /etc/sddm.conf with lines
[Users]
MinimumUid=500"

- "I have solved that issue by adding a kernel parameter in GRUB:
> sudo vi /etc/default/grub
Adding the following config:
GRUB_CMDLINE_LINUX_DEFAULT="rcutree.rcu_idle_gp_de lay=1"
> sudo update-grub"

-and "Upgrades are "plague"! A new install is faster than a laborious surch for an error."

[Snowhog]

Honestly, I think you are going to be much better off if you simply do a clean, fresh installation, formatting both / and /home. Hopefully you have a backup of any/all important data.

[GreyGeek]

That's the beauty of Btrfs !!!

Just before you make any potentially harmful changes you make dated snapshots of @ and @home. If things don't work out you rollback to those snapshots in less than 5 minutes rather than wasting hours a/o days trying to fix things.

[Simon]

Hello, I don't dual boot windows but I have 2 copies of Linux on my 1TB HDD. I don't use butter files system, as my friend above does, but that is not to say it isn't worth checking into.

On my primary partition I start with sda1 my current operating Linux and I allocate about 80 GB which is more than enough for the operating system. After that I have 20 GB for my boot and backup should I fry my OS (which happens when I experiment too often). Sure I could use the Live CD but having such a tiny space that I only use should the system get wonky is worth the effort. The only reason for me to dig out a Live CD would be if I could not boot at all. My boot is in sda2 a place I don't visit unless my sda1 fails.

After that in sd3 is my swap. Since swap is just an area Linux uses for keeping notes as such, I allow both to share it no need for more than one swap area.

The remainder of my drive is the meat and potatoes, the extended partition is where I keep my software, games, utilities, etc.. Yes, I keep that separate from the OS. A programmer and a great friend of mine told me to think of my computer as a house. Your drive space is like floor space. So I look at partitions are the walls between rooms. A great many of my games are downloads such as Guild Wars 2 at 21 GB and I sure don't want to wait for it to download again.

[GreyGeek]

A LiveUSB may be necessary even with a Btrfs installation if the operator makes a mistake ... like I did.

When I made a snapshot of @ I inadvertently used @home as the source. Needless to say, when I rolled back and rebooted my system couldn't find a bootable system because /home doesn't have it. After booting the LiveUSB I discovered the mixup and rolled back to the previous snapshot, after making sure they were @ and @home, not @home and @home. That added about 10 minutes to my rollback and taught me to not be so caviler about making snapshots. Toward that end I plan on creating a script to do the backups automatically, but haven't gotten around to it yet.

[Simon]

At least, you can take comfort, it was human operator error and not a problem with your BTFS.

[GreyGeek]

At least, you can take comfort, it was human operator error and not a problem with your BTFS.

Yup!
For me, Btrfs has been stable as a rock, even when I jack it around like I did.

[nicrnicr]

Thank you Snowhog, GreyGeek and Simon for your answers! :-)
I installed Kubuntu 16.04 because I couldn't use Autokey on Kubuntu 14.04. As the wellcome screen from Kubuntu 16.04 is black, I come back to Kubuntu 14.04 and all the files that I had on Kubuntu 16.04 are accessible from Kubuntu 14.04 (which I didn't know - thanks Simon). Furthermore the Virtualbox works better on Kubuntu 14.04*than on Kubuntu 16.04.

@oshunluvr:*All the Kubuntu (at least from the version 14.04) have Bitcoin Core. When you use this software i.e. when you intend to receive and send bitcoins, there are much more than 400 GB Blockchain which are downloaded.

[GreyGeek]

...

@oshunluvr:*All the new Kubuntu have Bitcoin Core. When you use this software i.e. when you intend to receive and send bitcoins, there are much more than 400 GB Blockchain which are downloaded.

An interesting explanation and discussion of Blockchain. Especially the last 3 or 4 paragraphs.
https://medium.com/@GruPiotr/the-big...g-7cb4e3d42db2

[nicrnicr]

Thanks GreyGeek for the link.
Furthermore, the next sytem that I will install is FreeBSD.

[nicrnicr]

Hello oshunluvr, GreyGeek, vinnywright, Simon, Snowhog and the others,

As I wanted to install a BSD system on my sick kubuntu, I've been*thinking about having KDE on it, but But I've been thinking that KDE might be the problem on my Kubuntu 16.04 as I*could still give orders through the console. Therefore I*upgraded KDE and the problem has been solved (with:

sudo apt-add-repository ppa:kubuntu-ppa/backports
sudo apt update && sudo apt full-upgrade -y

)

The taskbar was still disappeared but I could install it again.