Hi there, looking into the same issues on multiple Bullseye systems, I can confirm the cause to be an incorrect /etc/nsswitch.conf.
After fixing that I had to reboot for the fix to work, I guess restarting some systemd or dbus service would have done the trick as well. Now for a proper fix: IMHO fwupd should either depend on libnss-systemd or disable the refresh service and timer in postinst if this recommended package is not present. Best wishes Philipp Huebner
