vboxvideo wrong ABI number for latest Debian Unstable XOrg Server -> duplicate of #12623

[planck_length]

After updating some xorg packages on Debian Unstable, X failed to start. I don't have the error log any more, but it said something about ABI 14 being incompatible with server ABI 15

I tried reinstalling guest additions, but I think it said something about an incompatible X version and didn't install the relevant driver (vboxvideo maybe?)

[planck_length]

This is the error I get when I try installing guest additions:

Removing existing VirtualBox DKMS kernel modules ...done.
Removing existing VirtualBox non-DKMS kernel modules ...done.
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 ...done.
Installing the Window System drivers
Warning: unknown version of the X Window System installed.  Not installing
X Window System drivers.
 ...done.
Installing graphics libraries and desktop services components ...done.

In particular the line:

Warning: unknown version of the X Window System installed. Not installing

[Michael Thayer]

Duplicate of #12623, fixed as of 27.1.2014 in version 4.3 and later.