How can I change the resolution on Virtual Box

Question

I installed eOS 5.0 on Virtual Box, its resolution is set to 800x600. How can I change it?
I tried installed virtualbox-guest by this command, but I stll cannot change the resolution.

sudo apt-get install virtualbox-guest-dkms

Answer 1

Ives,

I use VirtualBox almost daily. I have a MacBook Pro with Elementary OS 5.0 and the screen resizes just fine. I had two hoops to jump through first:

1. Add the Extension Pack
   a. Launch VirtualBox. Go to Help -> About VirtualBox. Make a note about the version.
   b. Go to the VirtualBox website. Click on Downloads.
   c. If your version of VirtualBox is not the latest, scroll down to VirtualBox older builds.
   d. Find the version number that matches what you found in step 1a.
   e. Download the Extension Pack for your version of VirtualBox.
   f. Go to your host's machine Downloads folder.
   g. Right click on Oracle_VM_VirtualBox_Extension... select Open in VirtualBox.
   h. Follow the instruction to install the Extension Pack.
   

2. Guest VM.
   a. Launch the guest VM where you want to expand the display.
   b. Login (if necessary).
   c. Go to Devices -> Insert Guest Additions CD image...
   NOTE: Depending on your version, VirtualBox may ask to download an .iso file, if this happens to you, respond yes (or OK) to the dialog prompt.
   d. Go to Applitations -> Files, under Devices you will see VBox_GAs_... click on that.
   e. On the top center of the screen you will see media > userID > VBox_GAs_...
   f. Right click on VBox_GAs_... Open with -> Terminal.
   g. At the Terminal prompt type: sudo ./VBoxLinuxAdditions.run
   h. After the installation is complete, reboot your Guest VM.
   i. You will see that you can click and drag the Guest VM window to whatever size works best for you.
   j. If all else fails, you could consider Full Screen Mode - Host+F for your Guest VM.
   

Good luck!

UPDATE:
This may fix the locked virtual CD issue.
1. Make sure that your Elementary OS VM is "powered down".
2. In the VirtualBox app, select the name of your virtual Elementary OS machine and click on the Settings icon.
3. Under Settings -> Storage, under Controller IDE: will be an indented selection. Right-click on VBoxGuestAdditions.iso, and select “Remove Attachment." There will be a confirmation box: click “remove”.
4. Click the “+” CD icon next to Controller IDE: to add new optical drive. A dialog box will open. Choose “Leave Empty”.
5. You will now see a CD icon with the word "Empty". Click the OK button to accept the changes.
6. Try the item 2 checklist again -- from the beginning.