Error while booting

[19yc93]

Hello,

I am new to Debian and i hope you can help me

After installation of Debian 9 stable with KDE desktop i can successfully boot. But while booting there are some error messages.
So the operating system seems to works but i want to know what errors occurred. Where can i find these error messages? In which log file?

If you need further information or something was not clear described please tell me.

Thanks
Greetings

[arochester]

https://wiki.debian.org/TroubleShooting ?

[lbuiyzxl]

Try "sudo journalctl"view all message of this boot.
To only view "fail":
"sudo journalctl |grep -i fail"

[dasein]

man dmesg

[debiman]

if it ain't broken, don't fix it.
error messages are normal - to some extent.
it could mean that some driver is trying to find non-existent hardware.
it could just be a warning.
thankfully, linux is flexible enough to be fine with that - again, to some extent.

if you like, you can cover those error messages with a boot splash.
it's what most "userfriendly" operating systems do.