Following Andy suggestion I looked for an offending file; running mkisofs with the debugger I found it. mkisofs hangs in the routine check_rr_dates, when is processing that file. It was a nautilus file with a very long name. I moved it into a directory by itself. Now I can reproduce the problem using that single file. Here is the name: $ls /tmp/nason/.nautilus/ metafiles $ls /tmp/nason/.nautilus/metafiles/ file:%2F%2F%2Fmnt%2Fcdrom%2Fbackup-2004-10-01-08%253A35%2Fusr%2Flocal%2Fhome%2Fnason%2Fc%252B%252B.xml Now I do: growisofs -Z /dev/hdd -root backup1 -R -D \ -graft-points /tmp/nason/.nautilus=/tmp/nason/.nautilus which works, and then growisofs -M /dev/hdd -root backup2 -old-root backup1 -R -D \ -graft-points /tmp/nason/.nautilus=/tmp/nason/.nautilus which hangs. If you want to try to reproduce the problem I attach a tar.gz file containing /tmp/nason/.nautilus/metafiles/* and /tmp/growisoprob which contains the two growisofs offending commands. -- Paolo Nason, INFN, sez. di Milano Universita' di Milano-Bicocca, Dip. di Fisica "G. Occhialini", Piazza della Scienza, 3 20126 Milano Phone: +39-02-64482541. Fax: +39-02-64482582.