Is there a way to make the Mac OS X guest OS adapt the resolution of the host OS given that there's no guest additions yet as of the moment?


There is no way for it to automatically adjust, but you can specify a custom resolution for the guest to use.

You can manually edit the VirtualBox configuration, and the boot file in OS X to use a custom resolution. It's a two part (Host VM/Guest) process to enable the resolution.

Here are the steps:

  1. First, make sure VirtualBox is not running. Close it if it is.

  2. Add the following setting to the <ExtraData> section of your VM's XML file (location C:\users\<username>\VirtualBox VMs\<OS_NAME>\<OS_NAME>.vbox-prev):

    <ExtraDataItem name="CustomVideoMode1" value="1680x1050x32"/>

    You can change the value above to your preferred display resolution, e.g. 1280x1024x32.

  3. Save the file and start your VM.

  4. In Mac open the /Extra folder in the Finder.

  5. Drag the com.app.Boot.plist file to the desktop.

  6. Open the file on the desktop in the editor.

  7. Locate the <key>Graphics Mode</key> entry, following that there should be a <string>xxxxxx</string> entry. Edit this entry to match the Custom Video entry from step 2 above. i.e. <string>1680x1050x32</string>

  8. Put file back, Restart your VM and the new display resolution should be effective.

Good Luck!

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  • 2
    This doesn't work. The only thing that seems to make a difference is using the solution described here: martinml.com/en/… – user41270 Jun 14 '11 at 7:42
  • This definitely doesn't work, the copy on the desktop is just ignored. See superuser.com/questions/478901/… for a more up-to-date method. – Sam Salisbury Mar 11 '13 at 15:19
  • @T.Todua: (1) Why do you suggest editing <OS_NAME>.vbox-prev instead of <OS_NAME>.vbox? (2) What do you mean by "Put file back"? – G-Man Says 'Reinstate Monica' Jan 16 '17 at 6:37

That should help solving your problem.

  • open this link
  • go down to Step 7: Make the Screen Bigger

Note: Install Multibeast 4.6.1 first (registration required)

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This is a bit late, but none of the other answers helped me. This video helped me. The instructions are very simple:

  1. Power off your VM

  2. Close VirtualBox, and any background processes (if applicable).

  3. In the following code, edit "VM Name" to be your VM name and "N" to be 0 for a screen resolution of 640 x 480, 1 for 800 x 600, 2 for 1024 x 768, 3 for 1280 x 1024, 4 for 1440 x 900, and 5 for 1900 x 1200:

    cd "C:\Program Files\Oracle\Virtualbox"

    VBoxManage setextradata "VM Name" VBoxInternal2/EfiGopMode N

  4. Run the code in command prompt as admin

That should get the job done. If anything is unclear, check out the linked video.

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