Problems installing Slack desktop

Trying to install the Slack desktop beta on 16.04 LTS, but receiving an error after running apt-get install on the .deb package:

Unpacking slack-desktop (2.1.2) ...
dpkg: error processing archive /home/Me/Downloads/slack-desktop-2.1.2-amd64.deb (--unpack): trying to overwrite /usr/share/doc/slack/copyright', which is also in package slack 0.15.2-7
dpkg-deb: error: subprocess paste was killed by signal (Broken pipe)
Errors were encountered while processing: /home/Me/Downloads/slack-desktop-2.1.2-amd64.deb
N: Can't drop privileges for downloading as file '/home/Me/Downloads/slack-desktop-2.1.2-amd64.deb' couldn't be accessed by user '_apt'. - pkgAcquire::Run (13: Permission denied)
E: Sub-process /usr/bin/dpkg returned an error code (1)

Looks like it's clashing with the slack 0.15.2-7 package, which I guess is some other, unrelated package that comes as standard with Ubuntu.

Any ideas on how to overcome this and install the slack desktop package?

I have found myself with the same problem. I solved by removing by hand the slack package, which is just some admin tool.

If your are on the directory you downloaded the package, this should do the work:

sudo apt-get remove slack && sudo dpkg -i slack-desktop-2.1.2-amd64.deb

Have below my full log:

xino@xinopc:~/Descargas$ sudo dpkg -i slack-desktop-2.1.2-amd64.deb 
[sudo] password for xino: 
(Leyendo la base de datos ... 255115 ficheros o directorios instalados actualmente.)
Preparando para desempaquetar slack-desktop-2.1.2-amd64.deb ...
Desempaquetando slack-desktop (2.1.2) ...
dpkg: error al procesar el archivo slack-desktop-2.1.2-amd64.deb (--install):
intentando sobreescribir `/usr/share/doc/slack/copyright', que está también en el paquete slack 0.15.2-7
dpkg-deb: error: el subproceso copiado fue terminado por la señal (Tubería rota)
Se encontraron errores al procesar:
slack-desktop-2.1.2-amd64.deb
xino@xinopc:~/Descargas$ sudo apt-get remove slack 
Leyendo lista de paquetes... Hecho
Creando árbol de dependencias       
Leyendo la información de estado... Hecho
Los paquetes indicados a continuación se instalaron de forma automática y ya no son necesarios.
  libappindicator1 libindicator7
Utilice «sudo apt autoremove» para eliminarlos.
Los siguientes paquetes se ELIMINARÁN:
  slack
0 actualizados, 0 nuevos se instalarán, 1 para eliminar y 0 no actualizados.
Se liberarán 174 kB después de esta operación.
¿Desea continuar? [S/n] s
(Leyendo la base de datos ... 255114 ficheros o directorios instalados actualmente.)
Desinstalando slack (0.15.2-7) ...
Procesando disparadores para man-db (2.7.5-1) ...
xino@xinopc:~/Descargas$ sudo dpkg -i slack-desktop-2.1.2-amd64.deb 
[sudo] password for xino: 
(Leyendo la base de datos ... 255091 ficheros o directorios instalados actualmente.)
Preparando para desempaquetar slack-desktop-2.1.2-amd64.deb ...
Desempaquetando slack-desktop (2.1.2) ...
Configurando slack-desktop (2.1.2) ...
Procesando disparadores para gnome-menus (3.13.3-6ubuntu3.1) ...
Procesando disparadores para desktop-file-utils (0.22-1ubuntu5) ...
Procesando disparadores para mime-support (3.59ubuntu1) ...

I also had the same problem. I dig little deeper into the problem and found that I had slack installed from Ubuntu Software Center.

Then I removed slack from Software Center, and reinstalled slack-desktop-2.1.2-amd64.deb. It installed properly.

Steps:

1. Open Ubuntu Software Center
2. Search for slack, and if found uninstall it
3. Reinstall slack-desktop-2.1.2-amd64.deb.