Hi, The non-booting machines have multiple CPUs: * X4200M2: 2 AMD 2220, no Xen, LVM * X2200M2: 2 AMD 2347HE The booting machine has multiple CPUs as well, but Xen is configured to give only 1 vCPU to Doms. * X4200M2: 2 AMD 2220, Xen The freezing machine might have a HW problem or might be hit by Debian bug #880554 as even after downgrading all DomU and Dom0 kernels, the freeze still occurs, even though it boots. Elmar