This is a companion discussion topic for the original entry at https://appimage.github.io/LosslessCut/
Oh boy… I think, here too, AppImage truly is just there to confuse. It is not user friendly that one has to chmod it via command line (or GUI, same difference, too many additional steps) for permissions! No two ways about it. Snaps and flatpaks have always worked at least for me.
sudo chmod a+x LosslessCut-linux.AppImage
[sudo] password for tux:
[21803:0328/115134.586394:FATAL:setuid_sandbox_host.cc(157)] The SUID sandbox helper binary was found, but is not configured correctly. Rather than run without sandboxing I’m aborting now. You need to make sure that /tmp/.mount_Lossle8FT943/chrome-sandbox is owned by root and has mode 4755.
 21803 trace trap ./LosslessCut-linux.AppImage
-and i can’t use the snap package on this Debian-based system. What to do? There is no .deb file at all?