I want to remove the Ubuntu MATE Welcome program, this is not useful as this is a single user installation. And no new or guest users will use the computer.
Meanwhile, you know you can tell Welcome not to open by unchecking the box bottom right of it Open Welcome when I Log On:
You'll never see it again :)
Don't try to remove it with apt though:
$ sudo apt remove ubuntu-mate-welcome -s Reading package lists... Done Building dependency tree Reading state information... Done The following packages will be REMOVED ubuntu-mate-desktop ubuntu-mate-welcome ^^^