Unable to restore LXC with idmapppings

[kalnas]

Getting error when trying to restore my LXC from GUI:

recovering backed-up configuration from 'pbs-iscsi:backup/ct/105/2026-02-26T23:18:18Z'
Using encryption key from file descriptor..   
Fingerprint: e0:6c:9f:e8:8b:99:d6:d3   
restoring 'pbs-iscsi:backup/ct/105/2026-02-26T23:18:18Z' now..
Using encryption key from file descriptor..   
Fingerprint: e0:6c:9f:e8:8b:99:d6:d3   
Warning: "/var/log/journal/f1f1f131cd994b67803d109e4744bbd4/user-1000.journal" - ACL invalid, attempting restore anyway..
Error: error extracting archive - encountered unexpected error during extraction: error at entry "user-1000.journal": failed to extract file: failed to apply acls: EINVAL: Invalid argument
TASK ERROR: unable to restore CT 105 - command 'lxc-usernsexec -m u:0:100000:1000 -m g:0:100000:1000 -m u:1000:1000:1 -m g:1000:1000:1 -m u:1001:101001:64535 -m g:1001:101001:64535 -- /usr/bin/proxmox-backup-client restore '--crypt-mode=encrypt' '--keyfd=13' ct/105/2026-02-26T23:18:18Z root.pxar /var/lib/lxc/105/rootfs --allow-existing-dirs --repository root@pam@192.168.1.16:truenas-iscsi' failed: exit code 255

The config:

arch: amd64
cores: 2
features: nesting=1
hostname: radarr
memory: 3072
mp0: /mnt/pve/MEDIA,mp=/shared_media,size=0T
net0: name=eth0,bridge=vmbr0,gw=192.168.1.5,hwaddr=7E:2D:B5:76:13:BC,ip=192.168.1.18/24,type=veth
onboot: 1
ostype: ubuntu
rootfs: data_mirored:subvol-105-disk-0,size=8G
swap: 1024
tags: 192.168.1.18
unprivileged: 1
lxc.idmap: u 0 100000 1000
lxc.idmap: g 0 100000 1000
lxc.idmap: u 1000 1000 1
lxc.idmap: g 1000 1000 1
lxc.idmap: u 1001 101001 64535
lxc.idmap: g 1001 101001 64535

I tried workarounb by restoring with non-root user, but then run into error

TASK ERROR: unable to restore CT 105 - restoring 'mp0' to bind mount is only possible for root

ProxMox version is 9.1.4

 

[Saron]

Could you share the output of pveversion -v on your pve host and also the pbs version?
In the meantime you can try restoring at least files with the --ignore-acls true flag:

proxmox-backup-client restore ct/105/2026-02-26T23:18:18Z root.pxar /path/to/your/restore --repository root@pam@192.168.1.16:truenas-iscsi --ignore-acls true -allow-existing-dirs --keyfile /path/to/encryption-key.json

Or if you still have the original container running, maybe cleaning up old journal files and creating a new backup helps...

 

[kalnas]

Could you share the output of pveversion -v on your pve host and also the pbs version?
In the meantime you can try restoring at least files with the --ignore-acls true flag:

proxmox-backup-client restore ct/105/2026-02-26T23:18:18Z root.pxar /path/to/your/restore --repository root@pam@192.168.1.16:truenas-iscsi --ignore-acls true -allow-existing-dirs --keyfile /path/to/encryption-key.json

Or if you still have the original container running, maybe cleaning up old journal files and creating a new backup helps...

Proxmox:

proxmox-ve: 9.1.0 (running kernel: 6.17.4-2-pve)
pve-manager: 9.1.4 (running version: 9.1.4/5ac30304265fbd8e)
proxmox-kernel-helper: 9.0.4
pve-kernel-5.13: 7.1-9
proxmox-kernel-6.17.4-2-pve-signed: 6.17.4-2
proxmox-kernel-6.17: 6.17.4-2
proxmox-kernel-6.17.4-1-pve-signed: 6.17.4-1
proxmox-kernel-6.14.11-5-pve-signed: 6.14.11-5
proxmox-kernel-6.14: 6.14.11-5
proxmox-kernel-6.14.11-4-pve-signed: 6.14.11-4
proxmox-kernel-6.14.11-3-pve-signed: 6.14.11-3
proxmox-kernel-6.14.11-1-pve-signed: 6.14.11-1
proxmox-kernel-6.14.8-2-pve-signed: 6.14.8-2
proxmox-kernel-6.8.12-13-pve-signed: 6.8.12-13
proxmox-kernel-6.8: 6.8.12-13
pve-kernel-5.13.19-6-pve: 5.13.19-15
pve-kernel-5.13.19-2-pve: 5.13.19-4
ceph-fuse: 19.2.3-pve2
corosync: 3.1.9-pve2
criu: 4.1.1-1
frr-pythontools: 10.4.1-1+pve1
ifupdown2: 3.3.0-1+pmx11
ksm-control-daemon: 1.5-1
libjs-extjs: 7.0.0-5
libproxmox-acme-perl: 1.7.0
libproxmox-backup-qemu0: 2.0.1
libproxmox-rs-perl: 0.4.1
libpve-access-control: 9.0.5
libpve-apiclient-perl: 3.4.2
libpve-cluster-api-perl: 9.0.7
libpve-cluster-perl: 9.0.7
libpve-common-perl: 9.1.4
libpve-guest-common-perl: 6.0.2
libpve-http-server-perl: 6.0.5
libpve-network-perl: 1.2.4
libpve-rs-perl: 0.11.4
libpve-storage-perl: 9.1.0
libspice-server1: 0.15.2-1+b1
lvm2: 2.03.31-2+pmx1
lxc-pve: 6.0.5-3
lxcfs: 6.0.4-pve1
novnc-pve: 1.6.0-3
proxmox-backup-client: 4.1.1-1
proxmox-backup-file-restore: 4.1.1-1
proxmox-backup-restore-image: 1.0.0
proxmox-firewall: 1.2.1
proxmox-kernel-helper: 9.0.4
proxmox-mail-forward: 1.0.2
proxmox-mini-journalreader: 1.6
proxmox-offline-mirror-helper: 0.7.3
proxmox-widget-toolkit: 5.1.5
pve-cluster: 9.0.7
pve-container: 6.0.18
pve-docs: 9.1.2
pve-edk2-firmware: 4.2025.05-2
pve-esxi-import-tools: 1.0.1
pve-firewall: 6.0.4
pve-firmware: 3.17-2
pve-ha-manager: 5.1.0
pve-i18n: 3.6.6
pve-qemu-kvm: 10.1.2-5
pve-xtermjs: 5.5.0-3
qemu-server: 9.1.3
smartmontools: 7.4-pve1
spiceterm: 3.4.1
swtpm: 0.8.0+pve3
vncterm: 1.9.1
zfsutils-linux: 2.3.4-pve1

pbs:

proxmox-backup-server 4.1.4-1 running version: 4.1.4

After a lot of trial and error was able to restore it with AI help and generated guide for next time: