I’m a complete noob about Ubuntu and use it on my office PC. These are the details of my release: Distributor ID: Ubuntu Description: Ubuntu 16.04.3 LTS Release: 16.04 Codename: xenial

I’ve used it without encountering any problem for the past 6-9 months. I have the habit of updating the system once a week or so (sudo apt-get update, sudo apt-get upgrade and sudo apt-get dist-upgrade) and everything seemed to work perfect till about 2 weeks ago.

Over the last 2 weeks though, running those commands started returning a host of errors. MY libreoffice was corrupt too and I uninstalled it to install a clean one, but to my shock I can’t install a new version either. I followed a lot of threads here and did a dozen things, which I’m afraid exacerbated my problem. I tried changing the servers and all, and in the process my “Software and Updates” stopped working completely.

Only my Synaptic Package Manager and it too returns the following error when I tried to reload packages.

Thanks in advance guys.

This is the message I get in Synaptic Package Manager.

The repository ‘http://ppa.launchpad.net/fossfreedom/packagefixes/ubuntu xenial Release’ does not have a Release file.Data from such a repository can’t be authenticated and is therefore potentially dangerous to use.See apt-secure(8) manpage for repository creation and user configuration details.Failed to fetch http://ppa.launchpad.net/shutter/ppa/ubuntu/dists/xenial/InRelease Clearsigned file isn’t valid, got ‘NOSPLIT’ (does the network require authentication?)Failed to fetch http://ppa.launchpad.net/teejee2008/ppa/ubuntu/dists/xenial/InRelease Clearsigned file isn’t valid, got ‘NOSPLIT’ (does the network require authentication?)Failed to fetch http://archive.ubuntu.com/ubuntu/dists/xenial-updates/main/binary-amd64/by-hash/SHA256/0a4e0e24b853ec1471eb50b0ab5283e8a0d0b02354c6e5eae58aaa290b5a4cae Hash Sum mismatchFailed to fetch http://archive.ubuntu.com/ubuntu/dists/xenial-updates/main/binary-i386/by-hash/SHA256/35e794894c94deb027edaca25b47857cff62ec832a1bbb10f2fb80ffa37139ba Failed to fetch http://archive.ubuntu.com/ubuntu/dists/xenial-proposed/restricted/i18n/by-hash/SHA256/fc96eae7d31ac4d530fdaa2afd2c90456b36536be702226efd2e3786056e1033 Hash Sum mismatchFailed to fetch http://ppa.launchpad.net/fossfreedom/packagefixes/ubuntu/dists/xenial/main/binary-amd64/Packages 404 Not FoundSome index files failed to download. They have been ignored, or old ones used instead.