Hi,
I can not reproduce this behavior. I started usbguard-notifier and
removed my yubikey and replugged it:
> ~ usbguard-notifier --debug
> Connection has been established
> LOG: src/Notifier.cpp::114 [DevicePresenceChanged] Device presence
changed signal
> LOG: src/Notifier.cpp::114 [DevicePresenceChanged] Device presence
changed signal
> LOG: src/Notifier.cpp::73 [DevicePolicyChanged] Device policy changed
signal
The crash message ("Failed to show notification") sounds to me as if
there is maybe no notification daemon running?
cheers,
Birger