Bug#1127158: Thunderbird fails to start after upgrade to gdk-pixbuf 2.44.5+dfsg-3 in unstable

[Debian Tester]

On 2/12/2026 10:43 AM, Jeremy Bicha wrote:
> On Mon, Feb 9, 2026 at 11:25 PM Debian Tester <frchuck278 at yahoo.com> wrote:
> > The failure is observed using Gnome, but thunderbird works fine in LXQt, presumably because
> > LXQt does not use gtk3.
> >
> > I waited until the fix for #1127558 migrated to my box hoping it would fix it, but it did not. The fix for #1127558
> > fixed a crash in LibreOffice, and I hoped that fix would fix my thunderbird, but it did not.
>
> In the future, please report a new bug for an issue like this. You can
> mention the bug number on existing bugs though. You might want to
> follow this bug:
> https://bugs.debian.org/1127710
>
> It might still be helpful for you to report a new bug. I don't know
> for sure whether your bug is the same as the other person's bug and it
> is easy to close duplicate bugs later. I don't believe we have enough
> information yet to understand what isn't working.
>
> Thank you,
> Jeremy Bícha

Thanks for your response. Yes, I think #1127710 is the same issue I am seeing.
As you said there, I expect it is related to this gdk-pixbuf transition. I agree
that you designate #1127710 as blocking #1127158.

To answer your questions to the OP of #1127710: About firefox on my box, it is not
affected and still works. I don't use Loupe. I also noticed a report that evince seems
affected by this transition and I don't know yet if evince works on my box either
because I don't use it. I also verified the Thunderbird bug exists on my box with Intel
integrated graphics and Raptor Lake CPU on the bare metal, and in both KVM/Qemu
and Xen/Qemu virtual environments, and in all cases the bug appears when
launching Thunderbird in Gnome. Reboot does not help.

As I mentioned in another message to #1127158, I can workaround this bug in
current sid by running Thunderbird under LXQt, presumably because the gdk-pixbuf
transition does not have as many adverse affects on environments based on Qt
instead of GTK. I have not tested other DEs such as KDE Plasma and XFCE. I would
expect XFCE would be more likely to be affected than KDE Plasma because, like
Gnome, it uses GTK.

I do have some skills to try to identify a cause of this bug, but unfortunately not
lots of time and I think it may take some time, but I think there is plenty of time
before Forky is released. Until instructed otherwise, I will send further reports
about this Thunderbird crash I am seeing to #1127710, per your request.

Cheers.