They are not.
Plex.tv is the hosted package.
The Ubuntu store provides a “Snap” container package which works very much like Docker and resides in a completely different area of the file system.
It is controlled through their Snap control panel. None of the commands I’ve given will work.
My recommendation is:
I will then be able to help you. (I use Fedora/Redhat – it has no Snap package support)
OK, I will do this. Is there anything worth backing up, etc before I do this?
With it in a SNAP container, we have no access to it. There isn’t any way to back it up. (another problem with SNAP containers)
You will unfortunately need to do this one from scratch.
OK, I don’t mind that.
I am having issues uninstalling the snap version now though, as it is telling me I need to create a snap account. Which I have done, but tit won’t recognise the details…I’ll come straight back here once I have got this version uninstalled
OK, got it all uninstalled.
Before I do a fresh install from command line, should I delete the old plexmediaserver folder in /var/lib/?
To make sure you start fresh:
Done.
It gave an error that the group plex didn’t exist.
Now, all you need do is:
I have downloaded it, so I have the file “plexmediaserver_1.17.0.1709-982421575_amd64.deb” sat in the downloads folder.
But when I use the command “sudo dpkg -i plexmediaserver_1.17.0.1709-982421575_amd64.deb.dpkg” it says there is no such file or directory
you need to have your terminal window IN the Downloads folder
cd ~/Downloads
sudo dpkg -i plexmediaserver_1.17.0.1709-982421575_amd64.deb
I got the following:
(Reading database … 181386 files and directories currently installed.)
Preparing to unpack plexmediaserver_1.17.0.1709-982421575_amd64.deb …
Unpacking plexmediaserver (1.17.0.1709-982421575) over (1.17.0.1709-982421575) …
Setting up plexmediaserver (1.17.0.1709-982421575) …
groups: ‘plex’: no such user
usermod: user ‘plex’ does not exist
dpkg: error processing package plexmediaserver (–install):
installed plexmediaserver package post-installation script subprocess returned error exit status 6
Processing triggers for libc-bin (2.29-0ubuntu2) …
Processing triggers for gnome-menus (3.32.0-1ubuntu1) …
Processing triggers for desktop-file-utils (0.23-4ubuntu1) …
Processing triggers for mime-support (3.60ubuntu1) …
Errors were encountered while processing:
plexmediaserver
that’s not right. There is something seriously wrong.
please copy/paste the following into the terminal window then copy/paste the output back here.
sudo sh
grep plex /etc/passwd
grep plex /etc/group
ls -la /var/lib/plexmediaserver
Nothing happens. When I type suso sh, it just moves to another line with a # on it. It doesn’t let me keep typing.
If I type the other commands, then it just move to a new command line.
The last command just returns a no such file or directory
If you cannot type on that command line after typing sudo sh, then your Ubuntu 19 installation is broken.
All sudo does is open a new shell session in the current window with admin/root privilege level (which is why it asks for the password)
If this is broken, your base OS is broken.
Odd numbered Ubuntu versions become EOL and are dropped on April 1 of the following year.
Even numbered Ubuntu versions get their minimal 3 year support.
LTS installations go much much longer.
I recommend you take 19 off and install 18.04 LTS if you intend to stay with Linux.
I can type after sudo sh. But it just put everything after a #
# is the command line prompt when in ROOT mode. This is normal
Oh, c**p. sorry. Im total Linux newbie.
So you just want me to type each of those other commands after the hash?
Do I do them one at a time and press enter each time?
I write everything so you can copy paste 
I suspected you’re new and making it copy/paste ready works the best .
If you’re experienced in Linux, it makes it that much easier too
So just paste that block of text you made copy-able in one go?
Copy / paste, one line at a time then press ENTER after each.
Each command will produce output.
