In order to run several Signal desktop instances in parallel, you can pass a –user-data-dir=<path> commandline option to signal-desktop.

First find out in which way your existing Signal instance was installed: For Flatpak, run

flatpak list | grep signal-desktop

For Snap, run

snap list signal-desktop

For distribution package run

dpkg -l signal-desktop

When Signal Desktop is installed via flatpak, do the following:

1. Copy /var/lib/flatpak/app/org.signal.Signal/current/active/files/share/applications/org.signal.Signal.desktop to ~/.local/share/applications/Signal2.desktop
2. Then edit ~/.local/share/applications/Signal2.desktop and change lines 2-3 as follows (replace <user> with your username):

   Name=Signal 2
   Exec=/usr/bin/flatpak run --branch=stable --arch=x86_64 --command=signal-desktop --file-forwarding org.signal.Signal --user-data-dir=/home/<user>/.var/app/org.signal.Signal/config/Signal2 @@u %U @@

Afterwards, you should find the second instance of Signal Desktop as „Signal 2“ in your application launcher.

Sometimes Signal asks you to verify that you're a human by solving a captcha. The link after the captcha is always opened by the default Signal client profile. You can change this temporarily by setting the Exec value of the .desktop file of the default Signal client:

In /var/lib/flatpak/app/org.signal.Signal/x86_64/stable/active/files/share/applications/org.signal.Signal.desktop:

Exec=/usr/bin/flatpak run --branch=stable --arch=x86_64 --command=signal-desktop --file-forwarding org.signal.Signal --user-data-dir=/home/<user>/.var/app/org.signal.Signal/config/Signal2 @@u %U @@

When Signal Desktop is installed via snap, do the following:

1. Copy /var/lib/snapd/desktop/applications/signal-desktop_signal-desktop.desktop to ~/.local/share/applications/Signal2.desktop
2. Then edit ~/.local/share/applications/Signal2.desktop and change lines 2-3 as follows (replace <user> with your username):

   Name=Signal 2
   Exec=env BAMF_DESKTOP_FILE_HINT=/var/lib/snapd/desktop/applications/signal-desktop_signal-desktop.desktop /snap/bin/signal-desktop --no-sandbox --user-data-dir=/home/<user>/snap/signal-desktop/current/.config/Signal2 %U

Afterwards, you should find the second instance of Signal Desktop as „Signal 2“ in your application launcher.

Display all files of signal-desktop package:

 dpkg -l signal-desktop

Find the file ending with .desktop This file describes how Signal Desktop is started via the launcher of your GUI. You can customize the file for a second Signal instance.

Copy the .desktop file into your local directory:

cp /usr/share/applications/signal-desktop.desktop ~/.local/share/applications/signal-desktop-ap.desktop

Find out the location of your Signal Desktop standard config directory. Possibly it is .config/Signal in your home directory (press Ctrl + h in order to see system folders in your home directory). When you found the location, create a new directory in the .config directory named like you want to name your new Signal instance, e.g. Signal2

mkdir ~/.config/Signal2

Find the .desktop file in your local directory and open it with a text editor.

Change the Name and Exec lines: Name is the name you assign to your new Signal instance, in this example Signal2. Exec describes the path to your newly created config directory:

Exec=/opt/Signal/signal-desktop -user-data-dir=path/to/folder %U

Your .desktop file should now look something like this:

[Desktop Entry]
Name=Signal2
Exec=/opt/Signal/signal-desktop -user-data-dir=/home/user/.config/Signal2 %U
Terminal=false
Type=Application
Icon=signal-desktop
StartupWMClass=Signal
Comment=Private messaging from your desktop
MimeType=x-scheme-handler/sgnl;x-scheme-handler/signalcaptcha;
Categories=Network;InstantMessaging;Chat;

Save the file. You should now find your new instance Signal2 in your application launcher.