I have VirtualBox software running on Windows 10 host with Ubuntu 16.04 LTS. It was running perfectly well with Guest Additions providing me with a shared clipboard, shared folder and full screen.
Recently I upgraded to the latest version, 5.2.8 and decided to upgrade the Guest Additions as well, following the instructions in the manual, mount ISO and then do:
cd VBox_GAs_5.2.8/ sudo ./VBoxLinuxAdditions.run
This is the output:
Verifying archive integrity... All good. Uncompressing VirtualBox 5.2.8 Guest Additions for Linux........ VirtualBox Guest Additions installer Removing installed version 5.0.16 of VirtualBox Guest Additions... Removing existing VirtualBox DKMS kernel modules ...done. Removing existing VirtualBox non-DKMS kernel modules ...done. Copying additional installer modules ... Installing additional modules ... VirtualBox Guest Additions: Building the VirtualBox Guest Additions kernel modules. VirtualBox Guest Additions: Starting. VirtualBox Guest Additions: Building the VirtualBox Guest Additions kernel modules.
But start-up became slower, I got a tiny window, and no shared clipboard or folder.
So I reinstalled the previous version of Guest Additions. This was the output:
Verifying archive integrity... All good. Uncompressing VirtualBox 5.0.16 Guest Additions for Linux............ VirtualBox Guest Additions installer Removing installed version 5.2.8 of VirtualBox Guest Additions... Copying additional installer modules ... Installing additional modules ... Removing existing VirtualBox DKMS kernel modules ...done. Removing existing VirtualBox non-DKMS kernel modules ...done. Building the VirtualBox Guest Additions kernel modules ...done. Doing non-kernel setup of the Guest Additions ...done. Starting the VirtualBox Guest Additions ...fail! (modprobe vboxguest failed) Installing the Window System drivers Installing X.Org Server 1.18 modules ...done. Setting up the Window System to use the Guest Additions ...done. You may need to restart the the Window System (or just restart the guest system) to enable the Guest Additions. Installing graphics libraries and desktop services components ...done.
After reboot, I got my full screen back, to my delight. But was greeted by the following pop-up "VBoxClient: The VirtualBox kernel service is not running. Exiting". So I was not surprised that shared clipboard and folders were still broken.
I have exhausted my search for that message but could not find any answer online that helped my case.
One thing I tried was to re-install the previous version of VirtualBox along with the guest additions 5.0.16. But nothing changed. So I upgraded to VirtualBox 5.2.8 again but left the Guest Additions on the older version 5.0.16, since it at least provided me with full screen. But no shared folders or clipboard with Windows.
UPDATE: Eventually Guest Additions started working again on Guest Additions version 5.0.16 using the latest VirtualBox software (5.2.8). I can't say exactly what fixed it since I tried re-installing Guest Additions 5.0.16 many times without success. It's possible that it started working after I installed a standard Ubuntu update, but it's just a guess.