VNC by Virtual Machine Manager



I am using Virtual Machine Manager to VNC a KVM guest machine.
After about 20 minutes the guest machine is shouting down.
If I am closing the vnc, the guest machine is running for days.

Any ideas?

Guest machine:
Ubuntu 10.4

Server (the guest machine is running on):
Ubuntu 11.4 server
Compiled against library: libvir 0.8.8
Using library: libvir 0.8.8
Using API: QEMU 0.8.8
Running hypervisor: QEMU 0.14.0

Client (run’s the Virtual Machine Manager):
Ubuntu 11.04
Virtual Machine Manager 0.8.6