We have tested MAC OS X in our Virtual box and we tried to increase the resolution of MAC OS X and finally found the easiest way to increase the resolution size in Virtualbox.

If you are using the latest version of VirtualBox and looking for the solution to get full resolution for MAC OS X then this post will be helpful. We have tried several methods over the internet and found a simple XML configuration file can make changes in resolutions.

The latest version of Virtualbox and MAC supports EFI (Extensible Firmware Interface). Which supports 5 resolutions.

0 – 640×480
1 – 800×600
2 – 1024×768
3 – 1280×1024
4 – 1440×900

If you have installed or if you plan to install MAC OS X in Virtualbox we recommend editing the XML file after creating the virtual machine for MAC OS. The XML file can be found in

C:\Documents and Settings\username\VirtualBoxMachines\Vmachinename\Vmachinename.xml

for Windows XP and in Windows 7 / Vista.

C:\Users\username\VirtualBoxMachines\Vmachinename\Vmachinename.xml

If you are using Linux you can find this XML file under /home folder.

Find out <ExtraDataItem> in the XML file and enter the following code and start your MAC virtual machine.

<ExtraDataItem name="VBoxInternal2/EfiGopMode" value="4"/>
<ExtraDataItem name="VBoxInternal2/UgaHorizontalResolution" value="1440"/>
<ExtraDataItem name="VBoxInternal2/UgaVerticalResolution" value="900"/>

Note: You can change the values for the extradata item. If you face audio problems after installing Mac you can download and install audio driver for Mac directly in this virtualbox link.

Update:
If your changes in the XML file is not reflecting in VirtualBox? then we suggest you reinstall VirtualBox. After reinstalling VirtualBox, we got the resolution.