Hi,
How to reproduce
On a updated system from Sunday 3 September, connect a Wacom tablet (Intuos4Medium here) via USB and try to configure it via the configuration panel ( a dedicated icon Wacom/Tablet exists on it ).
Result
It is impossible to configure the tablet. Nothing happen. The icon refuse to launch.
Trying to launch the configuration system via terminal get this output:
Wacom: crash, "schema 'org.gnome.settings-daemon.peripherals.wacom' is not installed"
Information
I wanted to acknowledge PureOS team of this issue, even if it's an upstream one.
It's in Debian-testing since more than 10 days (a half pushed GNOME desktop environment, conflict 3.22/3.24 as far as I understand).
It really block my adoption of PureOS: not your fault, but adopting Debian-testing is too dangerous for professional artist living with a tablet.
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=872875
Workaround
Downgrading the gnome-settings-daemon to 3.22 doesn't work for my tablet model.
It improves the situation: I can now open the configuration panel; but no settings apply to the tablet.
Also, the app "Software" become crazy after a downgrade and prompt user for updating all the time...
wget http://ftp.uk.debian.org/debian/pool/main/g/gnome-settings-daemon/gnome-settings-daemon_3.22.2-2%2Bdeb9u2_amd64.deb sudo dpkg -i gnome-settings-daemon_3.22.2-2+deb9u2_amd64.deb
Configuring manually the tablet via xsetwacom command-line could work, but then it's a fight against the desktop-environment to reapply the script all the time:
Screenlock reset the the default config, no way in GNOME to add a startup bash script, etc...