When setting up a virtual machine with a 32 bit Lubuntu on a 64 bit Windows 8.1 system I had a hard time figuring out how to make sure the copy-and-paste functionality worked across the two systems as it should. Information about this on the internet is scattered and mostly incorrect. With a lot of research and trial and error I figured the correct set of steps needed.

I haven’t tried the below steps with other Linux systems, but I guess they would be identical for similar *buntu systems and similar for other flavours of Linux.

Note: these instructions are specific to the Oracle VM VirtualBox version 4.3.28.

1. In the VM’s settings make sure Shared Clipboard is set to Bidirectional.
   
2. Start your freshly installed Lubuntu Virtual Machine.
3. Make sure it’s fully updated, then reboot the VM.
   
   Shell

   sudo apt-get update sudo apt-get upgrade sudo reboot

   1 2 3

   sudo apt-get update sudo apt-get upgrade sudo reboot

4. Install some prerequisites:
   
   Shell

   sudo apt-get install gcc dkms build-essential linux-headers-generic

   1	sudo apt-get install gcc dkms build-essential linux-headers-generic

5. Insert the Guest Additions CD image by clicking Devices -> Insert Guest Additions CD image in the virtual machine’s toolbar.
6. Install the Guest Additions:
   
   Shell

   sudo /media/dev/VBOXADDITIONS_4.3.28_100309/VBoxLinuxAdditions.run

   1	sudo /media/dev/VBOXADDITIONS_4.3.28_100309/VBoxLinuxAdditions.run

7. Reboot the VM.

The installation takes a couple of minutes, depending on your configuration.

After restarting the OS copy/paste should work normally between the two OSs.