Failed to fetch http://ppa.launchpad.net

Question

When I run

sudo apt-get update

I always get this output:

...

E: Failed to fetch http://ppa.launchpad.net/q-quark/equalx/ubuntu/dists/xenial/main/source/Sources  404  Not Found
E: Some index files failed to download. They have been ignored, or old ones used instead

How could I fix it?

Solution 1

This PPA does not exist; that's why it is returning 404

1. Check this PPA entry in /etc/apt/sources.list and /etc/apt/sources.list.d/* and delete entry similar:

   deb  http://ppa.launchpad.net/q-quark/equalx/ubuntu xenial main
   

2. After that run command:

   sudo apt-get update
   

Solution 2

404 is Internet slang for "Object not found". Some research at the source site shows that equalx is provided for the Saucy (13.10) and Trusty (14.04) releases. You're asking for xenial.

Either wait until the developer updates the PPA, or download the source and build it for Xenial yourself (this is hard).