Thank you for your swift and detailed response, intrigeri. I've tried your solution, and I confirm that now the guest shuts down correctly.
Still I cannot add an external USB drive from the virtual machine manager. When the guest is running and I try and add it, I get the following messages. I don't know whether this issue is also related. I had noticed it even before your correction. Perhaps I should submit a new bug report? All in all, it seems that my configuration (apparmor with a backported kernel) is pretty unusual, but still I think it's worth considering it since when you use a backported kernel in stretch, then apparmor is installed and activated by default (perhaps this is no longer the case?) Cheers, solitone -- Logs Jan 15 06:35:23 kernel: audit: type=1400 audit(1515994523.376:83): apparmor="STATUS" operation="profile_replace" profile="unconfined" name="libvirt-86d03398-41ea-4eb6-a6ea-d2a2986a6a56" pid=3793 comm="apparmor_parser" Jan 15 06:35:23 kernel: audit: type=1400 audit(1515994523.380:84): apparmor="DENIED" operation="open" profile="libvirt-86d03398-41ea-4eb6-a6ea-d2a2986a6a56" name="/run/udev/data/+usb:1-2:1.0" pid=3759 comm="qemu-system-x86" requested_mask="r" denied_mask="r" fsuid=1000 ouid=0 Jan 15 06:35:23 kernel: audit: type=1400 audit(1515994523.380:85): apparmor="DENIED" operation="open" profile="libvirt-86d03398-41ea-4eb6-a6ea-d2a2986a6a56" name="/run/udev/data/c189:129" pid=3759 comm="qemu-system-x86" requested_mask="r" denied_mask="r" fsuid=1000 ouid=0 Jan 15 06:35:23 kernel: audit: type=1400 audit(1515994523.380:86): apparmor="DENIED" operation="open" profile="libvirt-86d03398-41ea-4eb6-a6ea-d2a2986a6a56" name="/run/udev/data/+usb:1-3:1.4" pid=3759 comm="qemu-system-x86" requested_mask="r" denied_mask="r" fsuid=1000 ouid=0 Jan 15 06:35:23 kernel: audit: type=1400 audit(1515994523.380:87): apparmor="DENIED" operation="open" profile="libvirt-86d03398-41ea-4eb6-a6ea-d2a2986a6a56" name="/run/udev/data/c189:0" pid=3759 comm="qemu-system-x86" requested_mask="r" denied_mask="r" fsuid=1000 ouid=0 Jan 15 06:35:23 kernel: audit: type=1400 audit(1515994523.380:88): apparmor="DENIED" operation="open" profile="libvirt-86d03398-41ea-4eb6-a6ea-d2a2986a6a56" name="/run/udev/data/+usb:1-5:1.3" pid=3759 comm="qemu-system-x86" requested_mask="r" denied_mask="r" fsuid=1000 ouid=0 Jan 15 06:35:23 kernel: audit: type=1400 audit(1515994523.380:89): apparmor="DENIED" operation="open" profile="libvirt-86d03398-41ea-4eb6-a6ea-d2a2986a6a56" name="/run/udev/data/+usb:1-3:1.2" pid=3759 comm="qemu-system-x86" requested_mask="r" denied_mask="r" fsuid=1000 ouid=0 Jan 15 06:35:23 kernel: audit: type=1400 audit(1515994523.380:90): apparmor="DENIED" operation="open" profile="libvirt-86d03398-41ea-4eb6-a6ea-d2a2986a6a56" name="/run/udev/data/c189:3" pid=3759 comm="qemu-system-x86" requested_mask="r" denied_mask="r" fsuid=1000 ouid=0 Jan 15 06:35:23 kernel: audit: type=1400 audit(1515994523.380:91): apparmor="DENIED" operation="open" profile="libvirt-86d03398-41ea-4eb6-a6ea-d2a2986a6a56" name="/run/udev/data/+usb:1-5:1.1" pid=3759 comm="qemu-system-x86" requested_mask="r" denied_mask="r" fsuid=1000 ouid=0 Jan 15 06:35:23 kernel: audit: type=1400 audit(1515994523.380:92): apparmor="DENIED" operation="open" profile="libvirt-86d03398-41ea-4eb6-a6ea-d2a2986a6a56" name="/run/udev/data/+usb:1-3:1.0" pid=3759 comm="qemu-system-x86" requested_mask="r" denied_mask="r" fsuid=1000 ouid=0
