Higher screen resolution in VirtualBox?

You need to install the VBox guest utilities to add support for the virtualised graphics hardware.

sudo apt-get install virtualbox-guest-utils virtualbox-guest-x11 virtualbox-guest-dkms

Previously you might have needed the "ose" versions:

sudo apt-get install virtualbox-ose-guest-utils virtualbox-ose-guest-x11 virtualbox-ose-guest-dkms

Edit:

http://www.linuxformat.com/forums/viewtopic.php?p=103289

1. Start Virtual box and log into Ubuntu.

2. Hit the right ctrl key so you can get your mouse pointer outside the virtual machine.

3.Go to top of virtual window, click on devices then select "Install Guest Additions" You will see a window pop up inside Ubuntu showing you that there are some new files mounted in a virtual CDROM drive. One of those files should be VBoxLinuxAdditions.run

You must run the file with some admin permissions so do that this way...

1. Click inside the Ubuntu screen again then go to Applications - Accessories then Terminal. The terminal window is where you will run the file from, but first we must navigate to the correct directory.

2. type this... cd /media/cdrom0 (then hit enter, there is a space after cd!)

3. next type... dir (You should see amongst the files displayed VBoxLinuxAdditions.run)

4. now type... sudo sh ./VBoxLinuxAdditions.run (yes, that is a full stop before the slash!)

after you hit enter and it has done its stuff, the files are now accessable from Ubuntu.

1. You now need to reboot the virtual machine or press Ctrl+Alt+backspace.

2. Log onto the Ubuntu desktop and this time go to System - Preferences then Screen Resolution. You should now have more options than the three low res options you had at the beginning of the day!

if the resolution you want is not one of the newly listed ones then follow these steps...

1. Open the terminal window again (Applications - Accessories then Terminal)

2. Type... sudo gedit /etc/X11/xorg.conf (space after gedit and X11 must be capital X)

3. It will ask you for a password which is the same as you log in with.

4. The text editor loads and you should see a lot of text in the window. First make a backup of this file by going to "file" then "save as" and changing the filename to xorgbak.conf

5. You now need to hunt through the text until you see the display resolutions listed. The ones you will be concerned about will be listed under bit depth 24 or bit depth 16 (as these depths are the ones that give you a large amount of colors.)

6. The idea here is to have your favorite screen resolution included in this list. Do this by either inserting it before the other listed resolutions in the exact same manner or typing it over one of the others. (you will only need to do this for the ones under bit depth 24 and 16)

7. You must now do a "save as" but be careful here as this time we need to call the file xorg.conf again. If you just hit save here you would have saved the changes over the backup file you created!

8. You are done. Hit Ctrl+Alt+Backspace to restart your virtual box, log in and enjoy your new screen resolution options!

Devices > Install Guest Additions, let it run then log out.

When you've been returned to the login screen you'll see it's the full size of your monitor. Log in and you're good to go.

I had the same problem and then found out that if you launch the virtual machine > click "view" on the toolbar > click "auto-resize guest display, then your virtual machine will have the same screen resolution as your own screen.