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 ).
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"
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.
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...