Hi, > ‘lstat’ Probably this. > but that’s not quite a “shell”. If i could reproduce the problem then i would want a long time visible message about how large the ISO image file is after grub-mkrescue has ended successfully. This would give an opportunity to compare the size as produced in the VM with the size later perceived on the host machine (which is a VM, too, in my case). If the sizes differ, then the VM contraption is to blame. If the size is too small already in the VM that ran grub-mkrescue, then xorriso or the VM operating system are to blame. Since i am not yet able to reproduce the problem, i propose that you add the necessary code to then end of make-iso9660-image in gnu/build/vm.scm. Such a report message cannot harm, given the existing verbosity of the ISO build command. Next time you make an ISO, retrieve the last size messages of xorriso: ISO image produced: 500069 sectors Written to medium : 500069 sectors at LBA 0 the new message about the ISO image file size in bytes, and the size of the ISO image file size when it is finally ready for exposure in the web. (I have to stress that the problem is not fixed but only got a band aid of which it is not known whether its size will always be large enough.) Have a nice day :) Thomas