Why doesn't clipboard sharing work with Ubuntu 18.04 LTS inside VirtualBox 5.1.26?

Solution 1:

The problem is with the virtualbox-guest-x11 package missing.

Execute the below commands:

sudo apt-get update
sudo apt-get install virtualbox-guest-x11

If it asks you about keeping a file or installing the new one, select the new one.

sudo VBoxClient --clipboard

This should enable clipboard sharing. Make sure that Clipboard Sharing is set to Bidirectional under VM Settings in VirtualBox as seen here:

Solution 2:

The problem is old version of VirtualBox that has the old guest additions version. Updating VirtualBox to 5.2.8 helps in this case. After updating VirtualBox, the guest additions must be updated in the following way:

• Do sudo apt install linux-headers-$(uname -r) build-essential dkms if not done already.
• Select Devices -> Insert Guest Additions CD Image... from VirtualBox VM menu
• Follow the instructions
• Eject the CD from Ubuntu after installation is done
• Reboot the Ubuntu guest VM
• Select Devices -> Shared Clipboard -> Bidirectional from VirtualBox VM menu to ensure clipboard sharing is enabled

Now shared clipboard should work.