Console screen on LXC is fully black screen (black text on black background)

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brooklyngrit

Member
May 20, 2023
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Hi I'm on Proxmox 9.0.10 and my console screen on all my LXCs are black screens. I know there's text there because I can drag/click then copy/paste into a notepad and see the text. But the color of the text in web UI proxmox console screen seems to be black text on black screen

In my LXC options screen:
Console mode = tty

Hmm seems to work fine on Brave browser with white font but not my firefox

pveversion --verbose:
Rich (BB code): 
root@NAS:~# pveversion --verbose
proxmox-ve: 9.0.0 (running kernel: 6.14.11-2-pve)
pve-manager: 9.0.10 (running version: 9.0.10/deb1ca707ec72a89)
proxmox-kernel-helper: 9.0.4
proxmox-kernel-6.14.11-2-pve-signed: 6.14.11-2
proxmox-kernel-6.14: 6.14.11-2
proxmox-kernel-6.14.11-1-pve-signed: 6.14.11-1
proxmox-kernel-6.8.12-14-pve-signed: 6.8.12-14
proxmox-kernel-6.8: 6.8.12-14
ceph: 19.2.3-pve1
ceph-fuse: 19.2.3-pve1
corosync: 3.1.9-pve2
criu: 4.1.1-1
frr-pythontools: 10.3.1-1+pve4
ifupdown2: 3.3.0-1+pmx10
intel-microcode: 3.20250512.1
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: 9.0.3
libpve-apiclient-perl: 3.4.0
libpve-cluster-api-perl: 9.0.6
libpve-cluster-perl: 9.0.6
libpve-common-perl: 9.0.10
libpve-guest-common-perl: 6.0.2
libpve-http-server-perl: 6.0.4
libpve-network-perl: 1.1.8
libpve-rs-perl: 0.10.10
libpve-storage-perl: 9.0.13
libspice-server1: 0.15.2-1+b1
lvm2: 2.03.31-2+pmx1
lxc-pve: 6.0.5-1
lxcfs: 6.0.4-pve1
novnc-pve: 1.6.0-3
proxmox-backup-client: 4.0.15-1
proxmox-backup-file-restore: 4.0.15-1
proxmox-backup-restore-image: 1.0.0
proxmox-firewall: 1.1.2
proxmox-kernel-helper: 9.0.4
proxmox-mail-forward: 1.0.2
proxmox-mini-journalreader: 1.6
proxmox-offline-mirror-helper: 0.7.2
proxmox-widget-toolkit: 5.0.5
pve-cluster: 9.0.6
pve-container: 6.0.13
pve-docs: 9.0.8
pve-edk2-firmware: 4.2025.02-4
pve-esxi-import-tools: 1.0.1
pve-firewall: 6.0.3
pve-firmware: 3.16-4
pve-ha-manager: 5.0.4
pve-i18n: 3.6.0
pve-qemu-kvm: 10.0.2-4
pve-xtermjs: 5.5.0-2
qemu-server: 9.0.22
smartmontools: 7.4-pve1
spiceterm: 3.4.1
swtpm: 0.8.0+pve2
vncterm: 1.9.1
zfsutils-linux: 2.3.4-pve1
root@NAS:~#

apt policy:
Code: 
root@NAS:~# apt policy
Package files:
 100 /var/lib/dpkg/status
     release a=now
 500 http://download.proxmox.com/debian/pve trixie/pve-no-subscription amd64 Packages
     release o=Proxmox,a=stable,n=trixie,l=Proxmox Debian Repository,c=pve-no-subscription,b=amd64
     origin download.proxmox.com
 500 http://repository.netdata.cloud/repos/repoconfig/debian bookworm/ Packages
     release v=12,o=Netdata,n=bookworm,l=Netdata,c=
     origin repository.netdata.cloud
 500 http://repository.netdata.cloud/repos/stable/debian bookworm/ Packages
     release v=12,o=Netdata,n=bookworm,l=Netdata,c=
     origin repository.netdata.cloud
 500 http://security.debian.org/debian-security trixie-security/main amd64 Packages
     release v=13,o=Debian,a=stable-security,n=trixie-security,l=Debian-Security,c=main,b=amd64
     origin security.debian.org
 500 http://deb.debian.org/debian trixie-updates/main amd64 Packages
     release v=13-updates,o=Debian,a=stable-updates,n=trixie-updates,l=Debian,c=main,b=amd64
     origin deb.debian.org
 500 http://deb.debian.org/debian trixie/contrib amd64 Packages
     release v=13.1,o=Debian,a=stable,n=trixie,l=Debian,c=contrib,b=amd64
     origin deb.debian.org
 500 http://deb.debian.org/debian trixie/main amd64 Packages
     release v=13.1,o=Debian,a=stable,n=trixie,l=Debian,c=main,b=amd64
     origin deb.debian.org
 500 http://download.proxmox.com/debian/ceph-squid trixie/no-subscription amd64 Packages
     release o=Proxmox,a=stable,n=trixie,l=Proxmox Ceph 19 Squid Debian Repository,c=no-subscription,b=amd64
     origin download.proxmox.com
Pinned packages:
 
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Hi @brooklyngrit Did you find a solution?
i have the same problem the other way round: I have the black font on black background in chrome but it works in firefox.

Btw i am on Proxmox 9.1
 
I'm also hitting this, but I'm thinking it's something on the client as I have a good spread of nodes on 9.0.X and 9.1.X where it happens but I'm pretty sure some of them were working a few days ago and it is unlikely that all of them had that bug (if it was a bug).

Unfortunate thing is, no browser works on my machine even with a fresh user profile, also tried disabling graphics acceleration to no avail.

This happens on xterm.js consoles (on the node, on a CT), thing is, the text is "there" I can select and copy it, I just can't see it.

EDIT 2025-11-30:
1764476511513.png
Noticed something while installing VyOS, it can display a few characters from the login banner. It seems to be able to render a few Unicode characters, so maybe something to do with fonts.
 
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Same issue, black text on black background, I can highlight it and see what is happening, but everything is just black now. I'm fairly certain it's machine specific (client machine) as I have been logged in elsewhere and not had this issue until today on one specific PC (haven't went back and tried another yet)

EDIT:
I updated firefox and the issue went away. I am on Linux Mint 22.2 and had the flatpak firefox version installed. After moving to the apt version and restarting the browser it's now working fine.
 
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I noticed i have similar problems on other websites, too, so i started investigating again.

As already suspected in this thread, it was related to fonts.
The other websites showing the same problem were using the font family Courier for text, that was not displaying correctly.
fc-match -v "Courier" | sed -n 's/^\s*file:\s*"\(.*\)"/\1/p; s/^\s*fontformat:\s*"\(.*\)"/FORMAT=\1/p; s/^\s*postscriptname:\s*"\(.*\)"/PS=\1/p'
revealed, that for the Courier family, an old "Type 1" font from texlive was used. I think that could be problemativ in some situations, too. But exlucing this texlive font did NOT solve the problem.

I then used
for i in $(ps faux | grep opt/google/chrome | awk '{print $2}' ); do lsof -p $i | grep -E '\.(ttf|otf|ttc|pfb|pfa|t1)(\s|$)' ; done
(yes, i am using the original chrome :-D) to find out what font files chrome is actually using, finding out, that it would only take ttf fonts into account anyway.
From the list i could see it was also using some fonts installed with wine.

in the end, uninstalling wine-fonts solved the problem for me!
 
Last edited:
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thana said:
I noticed i have similar problems on other websites, too, so i started investigating again.

As already suspected in this thread, it was related to fonts.
The other websites showing the same problem were using the font family Courier for text, that was not displaying correctly.
fc-match -v "Courier" | sed -n 's/^\s*file:\s*"\(.*\)"/\1/p; s/^\s*fontformat:\s*"\(.*\)"/FORMAT=\1/p; s/^\s*postscriptname:\s*"\(.*\)"/PS=\1/p'
revealed, that for the Courier family, an old "Type 1" font from texlive was used. I think that could be problemativ in some situations, too. But exlucing this texlive font did NOT solve the problem.

I then used
for i in $(ps faux | grep opt/google/chrome | awk '{print $2}' ); do lsof -p $i | grep -E '\.(ttf|otf|ttc|pfb|pfa|t1)(\s|$)' ; done
(yes, i am using the original chrome :-D) to find out what font files chrome is actually using, finding out, that it would only take ttf fonts into account anyway.
From the list i could see it was also using some fonts installed with wine.

in the end, uninstalling wine-fonts solved the problem for me!
Click to expand...
Great sleuthing, thanks for sharing.

This was indeed also the case for me, I am on NixOS 25.11 and removing `winePackages.fonts` resolves the issue.
 
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