Hello, Trying a variant of this example from python/libvir.html: import libvirt import sys conn = libvirt.openReadOnly(None) if conn == None: print 'Failed to open connection to the hypervisor' sys.exit(1) dom0 = conn.lookupByName("Domain-0") if dom0 == None: print 'Failed to find the main domain' sys.exit(1) print "Domain 0: id %d running %s" % (dom0.ID(), dom0.OSType()) print dom0.info() I found that conn.lookupByName throws an exception when the specified name is not found. If the example is just out of date, it should use try:/except: instead of comparing dom0 to None, shouldn't it? You can demonstrate it like this: $ python -c 'import libvirt; libvirt.openReadOnly(None).lookupByName("x")' libvir: Xen Daemon error : GET operation failed: No such domain x Traceback (most recent call last): File "<string>", line 1, in ? File "/usr/lib/python2.4/site-packages/libvirt.py", line 213, in lookupByName if ret is None:raise libvirtError('virDomainLookupByName() failed') libvirt.libvirtError: virDomainLookupByName() failed [Exit 1] Jim