Windows 11 fs mount not working anymore

Incus
, ,
1

Hi!

I use a windows 11 vm because my printer doesn’t work with linux, which worked fine until recently. At some point I had to use it again and realised that the directory that I mount in the VM no longer works, the virtio-fs service was not running anymore.

I tried starting it manually and got the error “Error 31: A device attached to this system is not functioning.”

This prompted me to check the device manager, where I found that there are three devices shown as not working; two “PCI Device” and one “PCI Simple Communications Controller”. I also see that the “Red Hat VirtIO SCSI pass-through controller” is working and using the correct driver.

I saw somewhere that it’s only two devices that are expected to not work, so maybe that third one is the problem?

My config looks like this:

architecture: x86_64
config:
  limits.cpu: "4"
  limits.memory: 6GiB
  volatile.SHARED.io.bus: virtiofs
  volatile.cloud-init.instance-id: 81366267-ad32-4782-a7c1-baa047ed3610
  volatile.eth0.host_name: tap131f1a4f
  volatile.eth0.hwaddr: 10:66:6a:9b:00:08
  volatile.last_state.power: RUNNING
  volatile.last_state.ready: "false"
  volatile.uuid: fd21ac92-d771-4217-b235-ac4501655fda
  volatile.uuid.generation: fd21ac92-d771-4217-b235-ac4501655fda
  volatile.vm.definition: pc-q35-10.1
  volatile.vm.rtc_adjustment: "7197"
  volatile.vm.rtc_offset: "0"
  volatile.vsock_id: "3526504903"
devices:
  SHARED:
    path: SHARED
    source: /tank/media/win11vm
    type: disk
  eth0:
    ipv4.address: 10.165.5.3
    name: eth0
    network: incusbr0
    security.ipv4_filtering: "true"
    security.ipv6_filtering: "true"
    security.mac_filtering: "true"
    type: nic
  install:
    boot.priority: "10"
    source: /home/borks/Downloads/Win11_24H2_26100.3915_x64.incus.iso
    type: disk
  printer:
    productid: 10ca
    type: usb
    vendorid: 04a9
  rdp-tcp:
    connect: tcp:0.0.0.0:3389
    listen: tcp:192.168.178.24:3389
    nat: "true"
    type: proxy
  rdp-udp:
    connect: udp:0.0.0.0:3389
    listen: udp:192.168.178.24:3389
    nat: "true"
    type: proxy
  root:
    path: /
    pool: default
    size: 55GiB
    type: disk
  vtpm:
    path: /dev/tpm0
    type: tpm
ephemeral: false
profiles:
- default
stateful: false
description: ""

Thanks in advance for your help!

2

Set image.os: Windows in there, reboot the VM and then download and install the latest version of the VirtIO drivers, that should get you all devices in a valid state.

3

Thanks, I missed that in the docs!

Unfortunately after setting image.os: Windows I don’t get any video output anymore, the incus console -t vga just gives me the Zabbly logo after the windows circling dots animation.

Using RDP just gives me a completely white screen.

Any ideas what the problem might be? I tried to use the ISO to repair the installation but no success.

Edit: Uninstalling the latest quality update fixed it :person_shrugging:

4

Even after re-installing the drivers, I still had a driverless device in device manager (the PCI Simple Communications Controller). I managed to get it to take a driver by manually making windows search the VirtIO driver ISO.

However even after this, I still get the same “Error 31: A device attached to this system is not functioning.”

Unless you have other ideas, think I’ll have to try to re-install the OS at this point :confused:

5

Maybe check if virtiofsd is running on the host. It could be that the Windows-side device error is about the host-side being somehow broken.

1 Like
6

I have two virtiofsd running, is that a problem?

root       33758  0.0  0.0   5664  1716 ?        SNs  Okt17   0:00 /opt/incus/bin/virtiofsd --fd=3 --cache=never --shared-dir=/var/lib/incus/devices/win11vm/disk.SHARED.SHARED --posix-acl
root       33760  0.0  0.0 6415408 1652 ?        SNl  Okt17   0:00 /opt/incus/bin/virtiofsd --fd=3 --cache=never --shared-dir=/var/lib/incus/devices/win11vm/disk.SHARED.SHARED --posix-acl
7

Nope, that’s normal, one should be the child of the other.

8

Unfortunately I had to give up on this, even a fresh install with a freshly downloaded Windows 11 ISO had the same issue and there was nothing that worked to resolve it.

9

Hi,

I’m new to Incus and am experiencing the exact same symptoms as unicorn. My VM OS is Windows 11 Pro. And in addition to what unicorn posted I also see the following in the logs, on the incus host:

[root@incus testincus]# cat /var/log/incus/win11vm/disk.SHARED.log
[2025-10-21T23:51:36Z INFO  virtiofsd] Waiting for vhost-user socket connection...
[2025-10-21T23:51:37Z INFO  virtiofsd] Client connected, servicing requests
Warning: Cannot announce submounts, client does not support it
[2025-10-21T23:54:09Z ERROR virtiofsd::passthrough] Cannot enable posix ACLs, client does not support it

The first two lines appear in the logs on VM startup and before the VirtIO-FS service is started. The last two lines appear when I attempt to start the service. I also receive the error 31, on the VM, when attempting to start the service.

Thanks for reading!

10

I think this is could have been caused by the pull request that addressed this issue:
VirtioFS posix_acl support · Issue #2345 · lxc/incus

I think the --posix-acl flag is being used by default.

11

Oh, fun… Okay, so that should be an easy fix, we can have the flag be skipped for Windows VMs.

12
1 Like
13

Thanks for this!

I noticed on the OS running incus that the “–posix-acl” flag was appearing with the virtiofsd process.

/opt/incus/bin/virtiofsd --fd=3 --cache=never --shared-dir=/var/lib/incus/devices/winvm1/disk.share1.share1 --posix-acl

I confirmed that removing the flag made the errors listed by @SiliconSurfer disappear.

1 Like