The issue occurs after detaching the monitor cable from the video output of the Ubuntu server. Even if screen capture can't work on such headless system, due to the graphics card being inactive, the nxnode process should fail gracefully.

When the issue occurs, the session log shows the following warnings:

1143641 1143655 2025-06-12 15:45:07 596.882 MonitorConfiguratorGnome: WARNING! Could not find monitor config with connector ']' to fill monitor modes.
1143641 1143655 2025-06-12 15:45:07 596.900 DBus monitor config: '()],[()],{renderer:native,layout-mode:2,legacy-ui-scaling-factor:1}'.
1143641 1143655 2025-06-12 15:45:07 596.905 MonitorConfiguratorGnome: WARNING! Failed to initialize monitor modes.

The nxnode process crashes with the following stack:

Thread 1 (Thread 0x77ba24ffd6c0 (LWP 53198)):
#0  0x000077ba32c5c2cc in GrdGrabber::createPipewires() () from /usr/NX/lib/libnxdimi.so
#1  0x000077ba32c5c657 in GrdGrabber::init() () from /usr/NX/lib/libnxdimi.so
#2  0x000077ba32c3c45a in WaylandPoller::setupGrabberObject() () from /usr/NX/lib/libnxdimi.so
#3  0x000077ba32c3f2cb in WaylandPoller::init() () from /usr/NX/lib/libnxdimi.so
#4  0x000077ba32c23b82 in NXShadowInit () from /usr/NX/lib/libnxdimi.so
#5  0x000077ba35caa1e0 in nxagentShadowInit () from /usr/NX/lib/libnxdiag.so
#6  0x000077ba35c87cdb in nxagentShadowClientCallback () from /usr/NX/lib/libnxdiag.so
#7  0x000077ba327358ac in _CallCallbacks () from /usr/NX/lib/libnxdifb.so
#8  0x000077ba3272e7bf in NextAvailableClient () from /usr/NX/lib/libnxdifb.so
#9  0x000077ba32799710 in ?? () from /usr/NX/lib/libnxdifb.so
#10 0x000077ba327351cb in ProcessWorkQueue () from /usr/NX/lib/libnxdifb.so
#11 0x000077ba327a1af0 in WaitForSomething () from /usr/NX/lib/libnxdifb.so
#12 0x000077ba3272ec8a in Dispatch () from /usr/NX/lib/libnxdifb.so
#13 0x000077ba32752ca1 in dix_main () from /usr/NX/lib/libnxdifb.so
#14 0x000077ba3407a404 in ?? () from /usr/NX/lib/libnxc.so
#15 0x000077ba3549caa4 in start_thread (arg=<optimized out>) at ./nptl/pthread_create.c:447
#16 0x000077ba35529c3c in clone3 () at ../sysdeps/unix/sysv/linux/x86_64/clone3.S:78