Hi Troy, some other package has to be updated together with xen: We do kickstart installs of para-VMs using virt-install. This worked fine before the kernel+xen update (SL 5.0). Afterwards, it would still work up to the point where the guest reboots. Virt-install would consistently tell me: Guest installation complete... restarting guest. libvir: Xen Daemon error : POST operation failed: (xend.err "Error creating domain: Boot loader didn't return any data!") exception was: virDomainCreate() failed POST operation failed: (xend.err "Error creating domain: Boot loader didn't return any data!") Domain installation may not have been successful. If it was, you can restart your domain by running 'virsh start ...'; otherwise, please restart your installation. Of course virsh start didn't work either, nor did xm create. This was reproducible (at least 3 times). I then updated the remaining packages from 5.1 (the host has a fairly minimal installation), and virsh start worked immediately. I append the list of packages that got updated. I still wonder which one it is, and unfortunately won't be able to find out for the next week: Updated: libgcc.x86_64 4.1.2-14.el5 Updated: glibc-common.x86_64 2.5-18.el5.1 Updated: glibc.x86_64 2.5-18.el5.1 Updated: libselinux.x86_64 1.33.4-4.el5 Updated: glibc.i686 2.5-18.el5.1 Updated: device-mapper.x86_64 1.02.20-1.el5 Updated: e2fsprogs-libs.x86_64 1.39-10.el5 Updated: module-init-tools.x86_64 3.3-0.pre3.1.34.el5 Updated: popt.x86_64 1.10.2-47.el5 Updated: audit-libs.x86_64 1.5.5-7.el5 Updated: nspr.x86_64 4.6.5-3.el5 Updated: udev.x86_64 095-14.9.el5 Updated: binutils.x86_64 2.17.50.0.6-5.el5 Updated: audit-libs.i386 1.5.5-7.el5 Updated: libselinux.i386 1.33.4-4.el5 Updated: libgcc.i386 4.1.2-14.el5 Updated: device-mapper.i386 1.02.20-1.el5 Updated: e2fsprogs-libs.i386 1.39-10.el5 Updated: e2fsprogs.x86_64 1.39-10.el5 Updated: initscripts.x86_64 8.45.17.EL-1 Updated: lvm2.x86_64 2.02.26-3.el5 Updated: kpartx.x86_64 0.4.7-12.el5 Updated: dmraid.x86_64 1.0.0.rc13-4.el5 Updated: nspr.i386 4.6.5-3.el5 Updated: nss.x86_64 3.11.7-1.3.el5 Updated: openafs.x86_64 1.4.5-56.SL5 Updated: nscd.x86_64 2.5-18.el5.1 Updated: libstdc++.i386 4.1.2-14.el5 Updated: mesa-libGL.i386 6.5.1-7.5.el5 Updated: audit-libs-python.x86_64 1.5.5-7.el5 Updated: mesa-libGL.x86_64 6.5.1-7.5.el5 Updated: libacl.x86_64 2.2.39-2.1.el5 Updated: bind-libs.x86_64 30:9.3.3-10.el5 Updated: libstdc++.x86_64 4.1.2-14.el5 Updated: libvolume_id.x86_64 095-14.9.el5 Updated: tcp_wrappers.x86_64 7.6-40.4.el5 Updated: gtk2.x86_64 2.10.4-19.el5 Updated: kernel-module-openafs-2.6.18-53.1.4.el5xen.x86_64 1.4.5-56.SL5 Updated: nss.i386 3.11.7-1.3.el5 Installed: device-mapper-multipath.x86_64 0.4.7-12.el5 Updated: sysklogd.x86_64 1.4.1-40.el5 Updated: vixie-cron.x86_64 4:4.1-72.el5 Updated: hwdata.noarch 0.211-1 Updated: libselinux-python.x86_64 1.33.4-4.el5 Updated: nash.x86_64 5.1.19.6-19 Updated: openafs-client.x86_64 1.4.5-56.SL5 Updated: evolution-data-server.x86_64 1.8.0-25.el5 Updated: nss_ldap.i386 253-5.el5 Updated: nss_ldap.x86_64 253-5.el5 Updated: pam_krb5.i386 2.2.14-1 Updated: parted.i386 1.8.1-12.el5 Updated: libuser.x86_64 0.54.7-2.el5.2 Updated: parted.x86_64 1.8.1-12.el5 Updated: pam_krb5.x86_64 2.2.14-1 Updated: cracklib.i386 2.8.9-3.3 Updated: tcp_wrappers.i386 7.6-40.4.el5 Updated: cracklib.x86_64 2.8.9-3.3 Updated: alsa-lib.x86_64 1.0.14-1.rc4.el5 Updated: openafs-compat.x86_64 1.4.5-56.SL5 Updated: mkinitrd.x86_64 5.1.19.6-19 Updated: mkinitrd.i386 5.1.19.6-19 Updated: nss-tools.x86_64 3.11.7-1.3.el5 Updated: conman.x86_64 0.1.9.2-8.el5 Updated: bind-utils.x86_64 30:9.3.3-10.el5 Updated: acl.x86_64 2.2.39-2.1.el5 Updated: audit.x86_64 1.5.5-7.el5 Updated: openafs-krb5.x86_64 1.4.5-56.SL5 Updated: pkinit-nss.x86_64 0.7.3-1.el5 Updated: microcode_ctl.x86_64 1:1.17-1.42.el5 Updated: dhclient.x86_64 12:3.0.5-7.el5 Updated: irqbalance.x86_64 2:0.55-6.el5 Updated: crash.x86_64 4.0-4.6.1 Updated: nfs-utils.x86_64 1:1.0.9-24.el5 Updated: prelink.x86_64 0.3.9-2.1 Updated: autofs.x86_64 1:5.0.1-0.rc2.55 Updated: cpuspeed.x86_64 1:1.2.1-1.48.el5 Updated: ypbind.x86_64 3:1.19-8.el5 Updated: xterm.x86_64 215-5.el5 Updated: ntp.x86_64 4.2.2p1-7.el5 Updated: redhat-menus.noarch 6.7.8-2.el5 Updated: cracklib-dicts.x86_64 2.8.9-3.3 Installed: sos.noarch 1.7-9.1.el5 Updated: Deployment_Guide-en-US.noarch 5.1.0-11 Updated: man-pages.noarch 2.39-10.el5 Updated: rpm-libs.x86_64 4.4.2-47.el5 Updated: hal.x86_64 0.5.8.1-25.el5.1 Updated: rpm.x86_64 4.4.2-47.el5 Updated: policycoreutils.x86_64 1.33.12-12.el5 Updated: redhat-lsb.i386 3.1-12.3.EL Updated: redhat-lsb.x86_64 3.1-12.3.EL Updated: rpm-python.x86_64 4.4.2-47.el5 Updated: kudzu.x86_64 1.2.57.1.15-1 Updated: system-config-network-tui.noarch 1.3.99-2.el5 Updated: pm-utils.x86_64 0.99.3-6.el5.17 Updated: selinux-policy.noarch 2.4.6-106.el5.3 Updated: firstboot-tui.noarch 1.4.27.3-1.el5 Updated: selinux-policy-targeted.noarch 2.4.6-106.el5.3 Erased: sysreport Updated: Deployment_Guide-en-US.noarch 5.1.0-11 -- Stephan Wiesand DESY - DV - Platanenallee 6 15738 Zeuthen, Germany