Ubuntu software not showing any software

Change the Download from server in Software & Updates. I had mine set on to a nearby Swedish one (which maybe itself has not updated yet). I changed to a more official looking UK server and Ubuntu software is now working.

This is most likely because newly installed systems lack a database of available packages. You can generate a recent one from the package repositories with the below steps.

1. Open a terminal. There are many ways to achieve that but the most common are to

   • type terminal in the dash and start the application of the same name or
   • press Ctrl+Alt+T.

2. Type or copy & paste the following commands into the terminal an run them:

   sudo apt update
   sudo apt upgrade -y
   

   (If you run into any errors in the process, please open a new question and include the entire output of these commands verbatim.)

3. Re-open Software Center and try again.

If sudo apt-get update && sudo apt-get upgrade followed by a restart doesn't fix the issue, I would suggest:

sudo apt-get dist-upgrade

Restart. If that doesn't help, you could also try backing up then deleting a folder in your home directory associated with the program. First, in Terminal or other CLI:

killall gnome-software

Then

mv ~/.local/share/gnome-software{,-BAK}

Reopen Ubuntu Software. (If needed, you can always undo the removal of the gnome-software folder and restore the backup: rm -r ~/.local/share/gnome-software && mv ~/.local/share/gnome-software{-BAK,})

Finally, if none of this works for you, I would be interested to know the output of:

find /etc/apt/ -name '*.list' -ls -exec cat {} \;

This is a list of all your allowed sources (sources are the repositories that contain the available software to download).

Although I can't think of any reason why you'd have nothing in sources.list, it's also the only explanation I can think of as to why nothing shows up as available in Ubuntu Software after trying all the normal troubleshooting steps.

Example output of the above command:

  1234567      4 -rw-r--r--   1 root     root         3026 Apr  8 22:39 /etc/apt/sources.list
# deb cdrom:[Ubuntu 16.04.1 LTS _Xenial Xerus_ - Release amd64 (20160719)]/ xenial main multiverse restricted universe

# See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
# newer versions of the distribution.
deb http://us.archive.ubuntu.com/ubuntu/ xenial main restricted
# deb-src http://us.archive.ubuntu.com/ubuntu/ xenial main restricted

## Major bug fix updates produced after the final release of the
## distribution.
deb http://us.archive.ubuntu.com/ubuntu/ xenial-updates main restricted
# deb-src http://us.archive.ubuntu.com/ubuntu/ xenial-updates main restricted

## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team, and may not be under a free licence. Please satisfy yourself as to
## your rights to use the software. Also, please note that software in
## universe WILL NOT receive any review or updates from the Ubuntu security
## team.
deb http://us.archive.ubuntu.com/ubuntu/ xenial universe
# deb-src http://us.archive.ubuntu.com/ubuntu/ xenial universe
deb http://us.archive.ubuntu.com/ubuntu/ xenial-updates universe
# deb-src http://us.archive.ubuntu.com/ubuntu/ xenial-updates universe

## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu 
## team, and may not be under a free licence. Please satisfy yourself as to 
## your rights to use the software. Also, please note that software in 
## multiverse WILL NOT receive any review or updates from the Ubuntu
## security team.
deb http://us.archive.ubuntu.com/ubuntu/ xenial multiverse
# deb-src http://us.archive.ubuntu.com/ubuntu/ xenial multiverse
deb http://us.archive.ubuntu.com/ubuntu/ xenial-updates multiverse
# deb-src http://us.archive.ubuntu.com/ubuntu/ xenial-updates multiverse

## N.B. software from this repository may not have been tested as
## extensively as that contained in the main release, although it includes
## newer versions of some applications which may provide useful features.
## Also, please note that software in backports WILL NOT receive any review
## or updates from the Ubuntu security team.
deb http://us.archive.ubuntu.com/ubuntu/ xenial-backports main restricted universe multiverse
# deb-src http://us.archive.ubuntu.com/ubuntu/ xenial-backports main restricted universe multiverse

## Uncomment the following two lines to add software from Canonical's
## 'partner' repository.
## This software is not part of Ubuntu, but is offered by Canonical and the
## respective vendors as a service to Ubuntu users.
## deb http://archive.canonical.com/ubuntu xenial partner
## deb-src http://archive.canonical.com/ubuntu xenial partner

deb http://security.ubuntu.com/ubuntu xenial-security main restricted
# deb-src http://security.ubuntu.com/ubuntu xenial-security main restricted
deb http://security.ubuntu.com/ubuntu xenial-security universe
# deb-src http://security.ubuntu.com/ubuntu xenial-security universe
deb http://security.ubuntu.com/ubuntu xenial-security multiverse
# deb-src http://security.ubuntu.com/ubuntu xenial-security multiverse

In the above example, the four main repositories are enabled.

1. Main - Canonical-supported free and open-source software.
2. Universe - Community-maintained free and open-source software.
3. Restricted - Proprietary drivers for devices.
4. Multiverse - Software restricted by copyright or legal issues.

Updates are also enabled. Repos with software from Canonical partners are not enabled. These represent the standard options that are enabled when you install Ubuntu for the first time.

If you had added any PPA's they would also appear in the output above.