Failed to download repository information: 16.04

[ray42]

Failed to download repository information: 16.04

My Gnome won't update, I get the above message.

When I click OK it then offers upgrade to 18.04.01 LTS

Is it ok with the following errors to upgrade?



W: The repository 'http://ppa.launchpad.net/cairo-dock-team/ppa/ubuntu xenial Release' does not have a Release file.
N: Data from such a repository can't be authenticated and is therefore potentially dangerous to use.
N: See apt-secure(8) manpage for repository creation and user configuration details.
E: Failed to fetch http://ppa.launchpad.net/cairo-dock-team/ppa/ubuntu/dists/xenial/main/binary-amd64/Packages 404 Not Found
E: Some index files failed to download. They have been ignored, or old ones used instead.


Also new software is not visible, and my installed apps won't show in software center, all but 3 of them. See pics.

https://www.dropbox.com/s/hqtg2droqo6cwnx/Screenshot%20from%202018-08-26%2014-38-47.png?dl=0

https://www.dropbox.com/s/fgic5dtjsakn4bm/Screenshot%20from%202018-08-26%2014-39-07.png?dl=0

[deadflowr]

Simple.
remove the cairo-dock ppa as it's no longer being updated for new releases.

[ray42]

That is done, but still leaves the big issue

[deadflowr]

That is done, but still leaves the big issue

What issue?

Edit:
If you mean the Software is still not showing all apps, then kill it and restart it.
gnome-software is always running in the background.
so try a simple killall gnome-software to kill it and then simply click on the Software icon to restart.
That should reload all properly.

(It can take sometime to reload; it's one of the reasons it's set as an always on app.)

[ray42]

Thanks but unfortunately it made no difference, see the links to images previously posted.

[ray42]

I upgraded oh dear oh dear black screen. I can get to grub menu but 18.04 LTS doesn't boot.

I did see one or two errors speeding past as it booted network manager didn't load, if that is important.

Helllpppp!!!

I now started a new request see link:

https://ubuntuforums.org/showthread.php?t=2399581&p=13795565#post13795565