Can't Attach USB Device to debian-13 App qube

marcos-morar · April 26, 2026, 5:57pm

When I try to attach a USB flash drive to a Debian 13-based app qube, it gives the following error:

Error: QubesException - device attach failed.

I checked journalctl and it showed this:

Complete Log from the Debian 13-based app qube

user@offline:~$ sudo journalctl -f -n0
Apr 26 17:09:33 offline qrexec-agent[1662]: 2026-04-26 17:09:33.962 qrexec-agent[1662]: qrexec-agent-data.c:274:handle_new_process_common: executed: root:QUBESRPC qubes.USBAttach dom0 (pid 1664)
Apr 26 17:09:33 offline qrexec-agent[1664]: pam_unix(qrexec:session): session opened for user root(uid=0) by (uid=0)
Apr 26 17:09:33 offline systemd[1]: Created slice user-0.slice - User Slice of UID 0.
Apr 26 17:09:33 offline systemd[1]: Starting user-runtime-dir@0.service - User Runtime Directory /run/user/0...
Apr 26 17:09:33 offline systemd[1]: Finished user-runtime-dir@0.service - User Runtime Directory /run/user/0.
Apr 26 17:09:33 offline systemd[1]: Starting user@0.service - User Manager for UID 0...
Apr 26 17:09:34 offline (systemd)[1668]: pam_unix(systemd-user:session): session opened for user root(uid=0) by root(uid=0)
Apr 26 17:09:34 offline systemd-logind[549]: New session 5 of user root.
Apr 26 17:09:34 offline systemd-xdg-autostart-generator[1677]: Exec binary '/usr/lib/qubes/show-hide-nm-applet.sh' does not exist: No such file or directory
Apr 26 17:09:34 offline systemd-xdg-autostart-generator[1677]: /etc/xdg/autostart/00-qubes-show-hide-nm-applet.desktop: not generating unit, executable specified in Exec= does not exist.
Apr 26 17:09:34 offline systemd-xdg-autostart-generator[1677]: Exec binary '/usr/bin/qubes-input-trigger' does not exist: No such file or directory
Apr 26 17:09:34 offline systemd-xdg-autostart-generator[1677]: /etc/xdg/autostart/qubes-input-trigger.desktop: not generating unit, executable specified in Exec= does not exist.
Apr 26 17:09:34 offline systemd[1668]: Queued start job for default target default.target.
Apr 26 17:09:34 offline systemd[1668]: Created slice app.slice - User Application Slice.
Apr 26 17:09:34 offline systemd[1668]: Created slice session.slice - User Core Session Slice.
Apr 26 17:09:34 offline systemd[1668]: Reached target paths.target - Paths.
Apr 26 17:09:34 offline systemd[1668]: Reached target timers.target - Timers.
Apr 26 17:09:34 offline systemd[1668]: Starting dbus.socket - D-Bus User Message Bus Socket...
Apr 26 17:09:34 offline systemd[1668]: Starting gcr-ssh-agent.socket - GCR ssh-agent wrapper...
Apr 26 17:09:34 offline systemd[1668]: Listening on gnome-keyring-daemon.socket - GNOME Keyring daemon.
Apr 26 17:09:34 offline systemd[1668]: pipewire-pulse.socket - PipeWire PulseAudio was skipped because of an unmet condition check (ConditionUser=!root).
Apr 26 17:09:34 offline systemd[1668]: pipewire.socket - PipeWire Multimedia System Sockets was skipped because of an unmet condition check (ConditionUser=!root).
Apr 26 17:09:34 offline systemd[1668]: Listening on speech-dispatcher.socket - Speech Dispatcher Socket.
Apr 26 17:09:34 offline systemd[1668]: Starting ssh-agent.socket - OpenSSH Agent socket...
Apr 26 17:09:34 offline systemd[1668]: Listening on gcr-ssh-agent.socket - GCR ssh-agent wrapper.
Apr 26 17:09:34 offline systemd[1668]: Listening on ssh-agent.socket - OpenSSH Agent socket.
Apr 26 17:09:34 offline systemd[1668]: Listening on dbus.socket - D-Bus User Message Bus Socket.
Apr 26 17:09:34 offline systemd[1668]: Reached target sockets.target - Sockets.
Apr 26 17:09:34 offline systemd[1668]: Reached target basic.target - Basic System.
Apr 26 17:09:34 offline systemd[1]: Started user@0.service - User Manager for UID 0.
Apr 26 17:09:34 offline systemd[1668]: Starting dbus.service - D-Bus User Message Bus...
Apr 26 17:09:34 offline systemd[1668]: pipewire.service - PipeWire Multimedia Service was skipped because of an unmet condition check (ConditionUser=!root).
Apr 26 17:09:34 offline systemd[1668]: filter-chain.service: Bound to unit pipewire.service, but unit isn't active.
Apr 26 17:09:34 offline systemd[1668]: Dependency failed for filter-chain.service - PipeWire filter chain daemon.
Apr 26 17:09:34 offline systemd[1668]: filter-chain.service: Job filter-chain.service/start failed with result 'dependency'.
Apr 26 17:09:34 offline systemd[1668]: wireplumber.service: Bound to unit pipewire.service, but unit isn't active.
Apr 26 17:09:34 offline systemd[1668]: Dependency failed for wireplumber.service - Multimedia Service Session Manager.
Apr 26 17:09:34 offline systemd[1668]: wireplumber.service: Job wireplumber.service/start failed with result 'dependency'.
Apr 26 17:09:34 offline systemd[1668]: pipewire-pulse.service - PipeWire PulseAudio was skipped because of an unmet condition check (ConditionUser=!root).
Apr 26 17:09:34 offline systemd[1668]: Reached target default.target - Main User Target.
Apr 26 17:09:34 offline systemd[1]: Started session-c7.scope - Session c7 of User root.
Apr 26 17:09:34 offline dbus-daemon[1685]: [session uid=0 pid=1685 pidfd=5] AppArmor D-Bus mediation is enabled
Apr 26 17:09:34 offline systemd[1668]: Started dbus.service - D-Bus User Message Bus.
Apr 26 17:09:34 offline systemd[1668]: Startup finished in 226ms.
Apr 26 17:09:35 offline qrexec-agent[1664]: pam_unix(qrexec:session): session closed for user root
Apr 26 17:09:35 offline qrexec-agent[1662]: 2026-04-26 17:09:35.619 qrexec-agent[1662]: qrexec-agent-data.c:309:handle_new_process_common: pid 1664 exited with 1
Apr 26 17:09:35 offline systemd[1]: session-c7.scope: Deactivated successfully.
Apr 26 17:09:45 offline systemd[1]: Stopping user@0.service - User Manager for UID 0...
Apr 26 17:09:45 offline systemd[1668]: Activating special unit exit.target...
Apr 26 17:09:45 offline systemd[1668]: Stopped target default.target - Main User Target.
Apr 26 17:09:45 offline systemd[1668]: Stopping dbus.service - D-Bus User Message Bus...
Apr 26 17:09:45 offline systemd[1668]: Stopped dbus.service - D-Bus User Message Bus.
Apr 26 17:09:45 offline systemd[1668]: Removed slice session.slice - User Core Session Slice.
Apr 26 17:09:45 offline systemd[1668]: Stopped target basic.target - Basic System.
Apr 26 17:09:45 offline systemd[1668]: Stopped target paths.target - Paths.
Apr 26 17:09:45 offline systemd[1668]: Stopped target sockets.target - Sockets.
Apr 26 17:09:45 offline systemd[1668]: Stopped target timers.target - Timers.
Apr 26 17:09:45 offline systemd[1668]: Closed dbus.socket - D-Bus User Message Bus Socket.
Apr 26 17:09:45 offline systemd[1668]: Closed gcr-ssh-agent.socket - GCR ssh-agent wrapper.
Apr 26 17:09:45 offline systemd[1668]: Closed gnome-keyring-daemon.socket - GNOME Keyring daemon.
Apr 26 17:09:45 offline systemd[1668]: Closed speech-dispatcher.socket - Speech Dispatcher Socket.
Apr 26 17:09:45 offline systemd[1668]: Stopping ssh-agent.socket - OpenSSH Agent socket...
Apr 26 17:09:45 offline systemd[1668]: Closed ssh-agent.socket - OpenSSH Agent socket.
Apr 26 17:09:45 offline systemd[1668]: Removed slice app.slice - User Application Slice.
Apr 26 17:09:45 offline systemd[1668]: Reached target shutdown.target - Shutdown.
Apr 26 17:09:45 offline systemd[1668]: Finished systemd-exit.service - Exit the Session.
Apr 26 17:09:45 offline systemd[1668]: Reached target exit.target - Exit the Session.
Apr 26 17:09:45 offline systemd-logind[549]: Removed session 5.
Apr 26 17:09:45 offline systemd[1]: user@0.service: Deactivated successfully.
Apr 26 17:09:45 offline systemd[1]: Stopped user@0.service - User Manager for UID 0.
Apr 26 17:09:45 offline systemd[1]: Stopping user-runtime-dir@0.service - User Runtime Directory /run/user/0...
Apr 26 17:09:45 offline systemd[1]: run-user-0.mount: Deactivated successfully.
Apr 26 17:09:45 offline systemd[1]: user-runtime-dir@0.service: Deactivated successfully.
Apr 26 17:09:45 offline systemd[1]: Stopped user-runtime-dir@0.service - User Runtime Directory /run/user/0.
Apr 26 17:09:45 offline systemd[1]: Removed slice user-0.slice - User Slice of UID 0.

I think the important part of this log is this:

Apr 26 17:09:34 offline systemd[1668]: Starting dbus.service - D-Bus User Message Bus...
Apr 26 17:09:34 offline systemd[1668]: pipewire.service - PipeWire Multimedia Service was skipped because of an unmet condition check (ConditionUser=!root).
Apr 26 17:09:34 offline systemd[1668]: filter-chain.service: Bound to unit pipewire.service, but unit isn't active.
Apr 26 17:09:34 offline systemd[1668]: Dependency failed for filter-chain.service - PipeWire filter chain daemon.
Apr 26 17:09:34 offline systemd[1668]: filter-chain.service: Job filter-chain.service/start failed with result 'dependency'.
Apr 26 17:09:34 offline systemd[1668]: wireplumber.service: Bound to unit pipewire.service, but unit isn't active.
Apr 26 17:09:34 offline systemd[1668]: Dependency failed for wireplumber.service - Multimedia Service Session Manager.
Apr 26 17:09:34 offline systemd[1668]: wireplumber.service: Job wireplumber.service/start failed with result 'dependency'.
Apr 26 17:09:34 offline systemd[1668]: pipewire-pulse.service - PipeWire PulseAudio was skipped because of an unmet condition check (ConditionUser=!root).

Can anyone help?

marcos-morar · April 26, 2026, 11:07pm

I was wrong about the “important part in the log”, that section was irrelevant.

After further checking, I discovered that qubes-usb-proxy is not installed by default in the debian-13-xfce template. This is why any app qube based on this template is unable to attach USB devices.

Installing the package resolves the issue.

The package should be installed by default in the debian-13-xfce template.

I have reported the bug here:

github.com/QubesOS/qubes-issues

qubes-usb-proxy missing in debian-13-xfce template

opened 11:05PM - 26 Apr 26 UTC

marcos-morar

P: default

### Qubes OS release Qubes OS 4.3 ### Brief summary The package `qubes-usb-pr…oxy` is not installed by default in the `debian-13-xfce` template. As a result, any app qube created from this template cannot attach USB devices. ### Steps to reproduce 1. Insert a USB flash drive (or any other USB device). 2. In the Qubes Devices widget , attempt to attach the USB device to the app qube based on debian-13 template. ### Expected behavior The USB device attaches successfully to the app qube without any error. The device appears inside the qube. ### Actual behavior The attachment immediately fails with the following error: `Error: QubesException - device attach failed.` ### Additional information Workaround: Manually install the package inside the template with `sudo apt install qubes-usb-proxy` and then shutdown the template and restart all app qubes based on it.

unman · April 27, 2026, 1:47am

It is.

I never presume to speak for the Qubes team.
When I comment in the Forum I speak for myself.

marcos-morar · April 27, 2026, 8:19am

I checked it on freshly installed 4.3 and its not.

parulin · April 27, 2026, 8:49am

Weird. Could you try to install a fresh debian-13-xfce template from the regular repo? Do you have qubes-vm-recommended? It should depend on qubes-usb-proxy.

unman · April 27, 2026, 10:41am

Let’s not duplicate between here and GitHub.
Resolve the issue in one place, and then add note in the other.

For the record 0:4.3.0-202512040043 does have the package installed, as
you can confirm.