So I just freshly installed Debian 9.1 with KDE and I'm getting the following errors after changing my sources.list file with
W: The repository [...] does not have a release file.
N: Data from such a repository can't be authenticated and is therefor potentially dangerous to use.
N: See apt-secure(8) manpage for repository creation and user configuration details.
N: Error fetching from [ip/updates/contrib/source/Sources] 404 Not found
E: Some index files couldn't be downloaded they got ignored or old ones were used instead.
This question is related to this one here but setting it to
stretch/updates doesn't help in my case.
I get these errors with all of the many sources I tried so far.
I could run
apt-get update && apt-get upgrade after some changes to the file; however 2 packages have been held back: firefox-esr.
Furthermore once after booting up it only showed blue but I could open the task manager. And once it froze when I tried to shutdown at the shutdown menu. Furthermore I also got
XDG_RUNTIME_DIR not set, defaulting to '/tmp/runtime-root' and
QStandardPaths: wrong ownership on runtime directory /run/user/0, 0 instead of 1000 earlier - but this might be another question.
Note that when I verified the DVD in the installer it told me it was fine, that I'm still new to Linux and that I'm having these errors after a fresh install.