you definitely need guest additions installed imo which i did.
I tried copying the original xorg.conf after installing a "plain" ubuntu 08.10 with guest additions, but no help
I have it setup with Enable 3D Acceleration checked
here is a plain xorg.conf
Section "Device"
Identifier "Configured Video Device"
EndSection
Section "Monitor"
Identifier "Configured Monitor"
EndSection
Section "Screen"
Identifier "Default Screen"
Monitor "Configured Monitor"
Device "Configured Video Device"
EndSection
here is the one after lmce install
Section "Device"
Identifier "Configured Video Device"
Option "XvmcUsesTextures" "true"
Option "renderAccel" "true"
Option "NoDDCValue"
Option "UseEDID" "true"
Option "ExactModeTimingsDVI" "true"
Option "NoLogo" "true"
Option "NoBandWidthTest" "true"
Option "ModeValidation" "NoDFPNativeResolutionCheck, NoEdidMaxPClkCheck, NoMaxPClkCheck, AllowInterlacedModes, AllowNon60HzDFPModes, NoEdidModes"
Option "DynamicTwinView" "false"
Option "UseEvents" "true"
Option "AllowGLXWithComposite" "true"
Option "AddARGBGLXVisuals" "true"
Option "ConnectedMonitor" "CRT"
EndSection
Section "Monitor"
Identifier "Configured Monitor"
Modeline "1024x768" 60.80 1024 1056 1128 1272 768 768 770 796
HorizSync 20-500
VertRefresh 59-61
EndSection
Section "Screen"
Identifier "Default Screen"
Monitor "Configured Monitor"
Device "Configured Video Device"
Option "XvmcUsesTextures" "true"
Option "renderAccel" "true"
Option "NoDDCValue"
Option "UseEDID" "true"
Option "ExactModeTimingsDVI" "true"
Option "NoLogo" "true"
Option "NoBandWidthTest" "true"
Option "ModeValidation" "NoDFPNativeResolutionCheck, NoEdidMaxPClkCheck, NoMaxPClkCheck, AllowInterlacedModes, AllowNon60HzDFPModes, NoEdidModes"
Option "DynamicTwinView" "false"
Option "UseEvents" "true"
Option "AllowGLXWithComposite" "true"
Option "AddARGBGLXVisuals" "true"
Option "TVStandard" "1024x768"
EndSection
Section "Extensions"
Option "Composite" "false"
Option "RENDER" "true"
EndSection
Section "ServerFlags"
Option "AutoAddDevices" "False"
EndSection
here is one where i added vboxvideo as the driver
Section "Device"
Identifier "Configured Video Device"
Driver "vboxvideo"
Option "XvmcUsesTextures" "true"
Option "renderAccel" "true"
Option "NoDDCValue"
Option "UseEDID" "true"
Option "ExactModeTimingsDVI" "true"
Option "NoLogo" "true"
Option "NoBandWidthTest" "true"
Option "ModeValidation" "NoDFPNativeResolutionCheck, NoEdidMaxPClkCheck, NoMaxPClkCheck, AllowInterlacedModes, AllowNon60HzDFPModes, NoEdidModes"
Option "DynamicTwinView" "false"
Option "UseEvents" "true"
Option "AllowGLXWithComposite" "true"
Option "AddARGBGLXVisuals" "true"
Option "ConnectedMonitor" "CRT"
EndSection
Section "Monitor"
Identifier "Configured Monitor"
Modeline "1024x768" 60.80 1024 1056 1128 1272 768 768 770 796
HorizSync 20-500
VertRefresh 59-61
EndSection
Section "Screen"
Identifier "Default Screen"
Monitor "Configured Monitor"
Device "Configured Video Device"
Option "XvmcUsesTextures" "true"
Option "renderAccel" "true"
Option "NoDDCValue"
Option "UseEDID" "true"
Option "ExactModeTimingsDVI" "true"
Option "NoLogo" "true"
Option "NoBandWidthTest" "true"
Option "ModeValidation" "NoDFPNativeResolutionCheck, NoEdidMaxPClkCheck, NoMaxPClkCheck, AllowInterlacedModes, AllowNon60HzDFPModes, NoEdidModes"
Option "DynamicTwinView" "false"
Option "UseEvents" "true"
Option "AllowGLXWithComposite" "true"
Option "AddARGBGLXVisuals" "true"
Option "TVStandard" "1024x768"
EndSection
Section "Extensions"
Option "Composite" "false"
Option "RENDER" "true"
EndSection
Section "ServerFlags"
Option "AutoAddDevices" "False"
EndSection
None of these do ui2 for me,
Richard