This is the result I get for sudo apt-get update

W: The repository 'http://ppa.launchpad.net/t-tujikawa/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/t-tujikawa/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.

How can I resolve this?

  • @karel doesn't look like a dependency issue to me Mar 23, 2018 at 9:17

2 Answers 2


This PPA does not support your version of ubuntu. You can see that from visiting the URL http://ppa.launchpad.net/t-tujikawa/ppa/ubuntu/dists/. There is not much you can do except hoping that it will be updated (not likely as this repository seems abandoned for a long time) or find another PPA for your purpose.


I found out that the error came because i have installed uGet downloader and it uses ppa from http://ppa.launchpad.net/t-tujikawa/ppa/ubuntu. So to fix this, open "Software & Updates" then select "other software" tab and find the site that caused the error(in my case, http://ppa.launchpad.net/t-tujikawa/ppa/ubuntu) and uncheck it and then give authentication then reload. Done.

  • Got it Your question was a bit misleading because it looked like you installed that ppa on purpose. Good you found a way to fix your problem. Mar 23, 2018 at 17:13

Not the answer you're looking for? Browse other questions tagged or ask your own question.