The problem I am currently facing is that I cannot start a guest domain on my domain-0 I am using version 3.0.4_1 version of xen''s source code. I compiled it to make a domain-0 kernel with all drivers. ( I used make install ). The domain 0 kernel compiled correctly and is now running, I can connect to the hypervisor through the virtual manager interface. The version of this kernel is 2.6.16.33-xen Now I am trying to use the same kernel as a guest domain, however I keep on getting an error (err 22: invalid argument). Most resurces on the internet state that this is a very generic error and carries very little information within. I also tried a kernel specifically compiled to act as a guest domain (make domainU), however I get the same results. The literature provided with the code states that the kernel compiled with all features can act as domain-0 and as guest domains. I am adding an excerpt from the xend-debug.log file Traceback (most recent call last): File "/usr/lib/python2.4/site-packages/xen/xend/server/SrvDomainDir.py", line 77, in op_create dominfo = self.xd.domain_create(config) File "/usr/lib/python2.4/site-packages/xen/xend/XendDomain.py", line 228, in domain_create dominfo = XendDomainInfo.create(config) File "/usr/lib/python2.4/site-packages/xen/xend/XendDomainInfo.py", line 194, in create vm.construct() File "/usr/lib/python2.4/site-packages/xen/xend/XendDomainInfo.py", line 1268, in construct handle = uuid.fromString(self.info[''uuid''])) Error: (22, ''Invalid argument'')