Ubuntu – How to uninstall programs in Ubuntu Mate 16.04

I ran into a similar problem. I would click the "Remove" button in the software center, but the applications would re-appear after a short period. I did this for the Aisle Riot Solitaire program, for example, and it kept coming back. When I went to remove it with the command line, however, it said it was not installed:

$ sudo apt-get purge aisleriot
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Package 'aisleriot' is not installed, so not removed
0 upgraded, 0 newly installed, 0 to remove and 87 not upgraded.

After more investigation (read: blind clicking), I discovered that clicking the refresh icon on the Updates tab actually seemed to refresh the Installed tab as well (even though the refresh icon is not available on the Installed tab). After this, Solitaire stopped showing up.

By "refresh icon", I mean the circular arrow in the upper left corner.

That's not quite true. No package operation should remove user data, ever, under any circumstances.

The reasoning for this is simple: The application doesn't own the data. You do.

Firstly, as an aside, other than the Ubuntu login screen, if an application asks you to log in, then your data is almost certainly not on your machine. The log in process is most likely related to an online authentication mechanism to provide access to your data stored somewhere else. Android and iOS have a (limited) ability to sync small amounts of user and configuration data for applications with "cloud" servers, but that doesn't necessarily disappear after uninstalling an application either.

All OSs (including Windows* and Android) are dependent on removal scripts. These presume that you want the software to go away but keep the configuration so that you can install it again later. The --purge option to apt merely removes configuration files.

If you're making modifications outside your own data (/home) then we assume you know what you're doing so your system continues to behave to your configuration. It's easy to rm -R the config files yourself, it's not so easy to get your specific customised version of things back the way you had set them up. So these scripts tend to err on the side of caution.

These scripts make various assumptions about what was installed and they are frequently written by humans who can make mistakes. Sometimes the software does something special, particularly when the software has dependencies.

We (Ubuntu developers) do do tests on test systems. We install the software into a clean installation of Ubuntu, and then we run apt remove and apt --purge remove and verify that the system returned to the expected (pre-installed) state.

If you do see a situation where a package is installed, no modifications are made to the config, and the package is then removed but files remain, then please file a bug against that package.

An alternative is to use snap, which houses the application entirely in its own environment.

*(in fact, this is one of the top ways Windows applications install malware, by "piggybacking" malware onto applications you choose to install, and then not removing them when you uninstall them.)