id summary reporter owner description type status component version resolution keywords cc guest host 1934 The VM is not started when enabling AMD-V. riker "I upgraded the Virtualbox from v1.6.2 to v1.6.4, and tried to enable the AMD-V to test a issue which I reported as the ID#1721. I run the test 5 times. I found the VM would not start successfully in the two rounds of the tests. I attached the log files for your reference. The system environment I used aer sumarized as below. Host System : Windows XP SP3. Virtualbox : v1.6.2 Guest System: Kubuntu v7.10 " defect closed VMM/HWACCM VirtualBox 1.6.4 duplicate Linux Windows