On Mon, Apr 07, 2014 at 10:12:05PM -0700, Stuart Young wrote: > Hi there, > > I was wondering if you could help me with a problem I'm having with > virt-sysprep. It's a recurrent problem running virt-sysprep: > > Examining the guest ... > Fatal error: exception Guestfs.Error("guestfs_launch failed. > See http://libguestfs.org/guestfs-faq.1.html#debugging-libguestfs > and/or run 'libguestfs-test-tool'.") > > So I ran virt-sysprep and libguestfs-test-tool after setting these: > > export LIBGUESTFS_DEBUG=1 > export LIBGUESTFS_TRACE=1 > > ... and have attached the output files. Thanks for the detailed debugging information. The bug is really very strange: mkdtemp: /tmp/lvmKOCUDb: No such file or directory It comes from this code in the appliance: https://github.com/libguestfs/libguestfs/blob/master/daemon/lvm-filter.c#L72 That link is to the latest upstream code. It hasn't changed at all since 1.20 (or for years before that), so I find it quite baffling why it is failing now. Is /tmp (on your host) a regular directory or have you moved it or symlinked it or done something else to it? You could try the following which should cause a real /tmp directory to be created in the appliance: mkdir tmp echo tmp | cpio --quiet -o -H newc > /usr/lib64/guestfs/supermin.d/00-tmp.img rmdir tmp Rich.