I'm new at this, but I'll do my best to explain. I installed OS X Mountain Lion on my VM Virtual Box and when I get to the part after I installed the 10.8 dvd iso. It says that "a critical error has occurred and virtual machine has stopped" and to report here what my log file says. So here it is: (PS: I have windows VIsta Home Premium edition(64bit) and the necessary 2gb and dual core processor
VirtualBox COM Server 4.3.12 r93733 win.amd64 (May 16 2014 13:57:11) release log
00:00:00.003000 main Log opened 2014-08-15T17:50:22.447198200Z
00:00:00.003000 main Build Type: release
00:00:00.003000 main OS Product: Windows Vista Home Premium Edition
00:00:00.003000 main OS Release: 6.0.6002
00:00:00.003000 main OS Service Pack: 2
00:00:00.298000 main DMI Product Name: FQ578AA-ABA s3707c
00:00:00.349000 main DMI Product Version:
00:00:00.349000 main Host RAM: 1790MB total, 658MB available
00:00:00.349000 main Executable: C:\Program Files\Oracle\VirtualBox\VBoxSVC.exe
00:00:00.349000 main Process ID: 7484
00:00:00.349000 main Package type: WINDOWS_64BITS_GENERIC
00:00:00.352000 Loading settings file "C:\Users\Donny/.VirtualBox\VirtualBox.xml" with version "1.12-windows"
00:00:01.836000 HostDnsMonitorProxy: Host's DNS information updated:
00:00:01.836000 DNS server 1: 209.18.47.61
00:00:01.836000 DNS server 2: 209.18.47.62
00:00:01.837000 VDInit finished
00:00:01.839000 Loading settings file "C:\Users\Donny\VirtualBox VMs\OS X Mountain Lion\OS X Mountain Lion.vbox" with version "1.14-windows"
00:00:26.227000 ERROR [COM]: aRC=VBOX_E_INVALID_VM_STATE (0x80bb0002) aIID={480cf695-2d8d-4256-9c7c-cce4184fa048} aComponent={Machine} aText={Machine is not locked for session (session state: Unlocked)}, preserve=false
00:00:27.064000 ERROR [COM]: aRC=VBOX_E_OBJECT_NOT_FOUND (0x80bb0001) aIID={3295e6ce-b051-47b2-9514-2c588bfe7554} aComponent={ExtPackManager} aText={No extension pack by the name 'Oracle VM VirtualBox Extension Pack' was found}, preserve=false
00:00:27.082000 ERROR [COM]: aRC=VBOX_E_IPRT_ERROR (0x80bb0005) aIID={480cf695-2d8d-4256-9c7c-cce4184fa048} aComponent={SessionMachine} aText={Saved screenshot data is not available (VERR_NOT_SUPPORTED)}, preserve=false
00:32:02.122000 ERROR [COM]: aRC=VBOX_E_INVALID_VM_STATE (0x80bb0002) aIID={480cf695-2d8d-4256-9c7c-cce4184fa048} aComponent={Machine} aText={Machine is not locked for session (session state: Unlocked)}, preserve=false
00:32:03.502000 ERROR [COM]: aRC=VBOX_E_OBJECT_NOT_FOUND (0x80bb0001) aIID={3295e6ce-b051-47b2-9514-2c588bfe7554} aComponent={ExtPackManager} aText={No extension pack by the name 'Oracle VM VirtualBox Extension Pack' was found}, preserve=false
00:32:03.560000 ERROR [COM]: aRC=VBOX_E_IPRT_ERROR (0x80bb0005) aIID={480cf695-2d8d-4256-9c7c-cce4184fa048} aComponent={SessionMachine} aText={Saved screenshot data is not available (VERR_NOT_SUPPORTED)}, preserve=false
00:41:59.398000 ERROR [COM]: aRC=E_ACCESSDENIED (0x80070005) aIID={05f2bbb6-a3a6-4fb9-9b49-6d0dda7142ac} aComponent={Medium} aText={The object is not ready}, preserve=false
00:46:33.768000 ERROR [COM]: aRC=E_FAIL (0x80004005) aIID={480cf695-2d8d-4256-9c7c-cce4184fa048} aComponent={Machine} aText={This machine does not have any snapshots}, preserve=false
00:47:45.438000 ERROR [COM]: aRC=VBOX_E_INVALID_VM_STATE (0x80bb0002) aIID={480cf695-2d8d-4256-9c7c-cce4184fa048} aComponent={Machine} aText={Machine is not locked for session (session state: Unlocked)}, preserve=false
00:47:46.288000 ERROR [COM]: aRC=VBOX_E_OBJECT_NOT_FOUND (0x80bb0001) aIID={3295e6ce-b051-47b2-9514-2c588bfe7554} aComponent={ExtPackManager} aText={No extension pack by the name 'Oracle VM VirtualBox Extension Pack' was found}, preserve=false
00:47:46.305000 ERROR [COM]: aRC=VBOX_E_IPRT_ERROR (0x80bb0005) aIID={480cf695-2d8d-4256-9c7c-cce4184fa048} aComponent={SessionMachine} aText={Saved screenshot data is not available (VERR_NOT_SUPPORTED)}, preserve=false
00:48:32.534000 ERROR [COM]: aRC=E_ACCESSDENIED (0x80070005) aIID={05f2bbb6-a3a6-4fb9-9b49-6d0dda7142ac} aComponent={Medium} aText={The object is not ready}, preserve=false
00:49:05.016000 ERROR [COM]: aRC=E_FAIL (0x80004005) aIID={480cf695-2d8d-4256-9c7c-cce4184fa048} aComponent={Machine} aText={This machine does not have any snapshots}, preserve=false
00:50:23.250000 ERROR [COM]: aRC=VBOX_E_INVALID_VM_STATE (0x80bb0002) aIID={480cf695-2d8d-4256-9c7c-cce4184fa048} aComponent={Machine} aText={Machine is not locked for session (session state: Unlocked)}, preserve=false
00:50:24.233000 ERROR [COM]: aRC=VBOX_E_OBJECT_NOT_FOUND (0x80bb0001) aIID={3295e6ce-b051-47b2-9514-2c588bfe7554} aComponent={ExtPackManager} aText={No extension pack by the name 'Oracle VM VirtualBox Extension Pack' was found}, preserve=false
00:50:24.248000 ERROR [COM]: aRC=VBOX_E_IPRT_ERROR (0x80bb0005) aIID={480cf695-2d8d-4256-9c7c-cce4184fa048} aComponent={SessionMachine} aText={Saved screenshot data is not available (VERR_NOT_SUPPORTED)}, preserve=false
00:54:37.792000 ERROR [COM]: aRC=VBOX_E_INVALID_VM_STATE (0x80bb0002) aIID={480cf695-2d8d-4256-9c7c-cce4184fa048} aComponent={Machine} aText={Machine is not locked for session (session state: Unlocked)}, preserve=false
00:54:38.768000 ERROR [COM]: aRC=VBOX_E_OBJECT_NOT_FOUND (0x80bb0001) aIID={3295e6ce-b051-47b2-9514-2c588bfe7554} aComponent={ExtPackManager} aText={No extension pack by the name 'Oracle VM VirtualBox Extension Pack' was found}, preserve=false
00:54:38.783000 ERROR [COM]: aRC=VBOX_E_IPRT_ERROR (0x80bb0005) aIID={480cf695-2d8d-4256-9c7c-cce4184fa048} aComponent={SessionMachine} aText={Saved screenshot data is not available (VERR_NOT_SUPPORTED)}, preserve=false
01:11:15.240000 ERROR [COM]: aRC=VBOX_E_INVALID_VM_STATE (0x80bb0002) aIID={480cf695-2d8d-4256-9c7c-cce4184fa048} aComponent={Machine} aText={Machine is not locked for session (session state: Unlocked)}, preserve=false
01:11:16.012000 ERROR [COM]: aRC=VBOX_E_OBJECT_NOT_FOUND (0x80bb0001) aIID={3295e6ce-b051-47b2-9514-2c588bfe7554} aComponent={ExtPackManager} aText={No extension pack by the name 'Oracle VM VirtualBox Extension Pack' was found}, preserve=false
01:11:16.030000 ERROR [COM]: aRC=VBOX_E_IPRT_ERROR (0x80bb0005) aIID={480cf695-2d8d-4256-9c7c-cce4184fa048} aComponent={SessionMachine} aText={Saved screenshot data is not available (VERR_NOT_SUPPORTED)}, preserve=false