Created attachment 141507 [details] Debug log generated by k3b at the end process. SUMMARY Written data are different from original data. STEPS TO REPRODUCE 1. Define directories to write, including hidden system files 2. Burn + verify 3. "The software 'mkisofs' returned an unknown error (code 13). OBSERVED RESULT M-Disk Verbatim BDXL 100Gb (blu-ray) is impossible to read. EXPECTED RESULT SOFTWARE/OS VERSIONS Linux Mint 20 (available in About System) KDE Plasma Version: ? KDE Frameworks Version: 5.68.0 Qt Version: 5.12.8 ADDITIONAL INFORMATION May be related to a system file named .DS_Store, to be engraved, as reported at the end of the debug lod attached.