Like i said, today i wanted to install some apps from app center and when i click it to install after a couple seconds an error messeage pop up. I think it is for some missing packages or repostorys from an unfinished system update, but when i try to update again i get the same error even the synaptick package manager gives me an error. This is the error i get

  • Can you please add another screenshot after changing your language temporarily to English so that it helps others understanding the error. Though its identical to an error "Failed to fetch updates" to me but I am not sure. In the meantime, be sure that you have a working internet connection when you are in the AppCenter.
    – Hasan
    Jan 31, 2019 at 8:39

2 Answers 2


Try running the following commands to repair your system

sudo apt-get update –fix-missing
sudo dpkg –configure -a
sudo apt-get install -f

Are you able to browse any websites? The error message states that there is an error while resolving the address of the update server (mx.archive.ubuntu.com). It also says that this particular server ist not (yet) available, so maybe it is a temporal issue. Have you tried again a few hours or days later?

In case you are not able to browse any sites I would suspect some issue with your DNS resolver. Try using a resolver that is not issued by your ISP, like,, or if your willing to give Google your information use or

  • Yes i am able to browse anything but unable to install anything, i think the error started because i accidentally interrumped a system update and later i tried to resume it but there wasn't any update to resume. Feb 1, 2019 at 4:00
  • "Error when performing the updates This could have been caused by adding external repositories manually or some corrupt source code file". that's the message i get when i open the software center and then i try to install something and another error pops up Feb 1, 2019 at 4:08

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