Ubuntu 12.04 fail start on VirtualBox 4.10 "Plymouth fail"

[undulatus]

BACKGROUND
system mac osx 10.7.5 running running ubuntu 12.04 on virtual box 4.8
My ubuntu 12.04 was working 12 hrs ago while using it I issued apt-get install git
AFAIK that was the only thing I changed in my system

as I boot my mac 12 hrs later I changed a setting in virtual box in enabled USB 2.0 (EHCI) controller
it said I need the virtual box extension pack
so I updated my VB to from 4.8 to 4.10 then install the pack

NOW
now as I start my ubuntu 12.04 on VB this appears

Starting the VirtualBox Guest Additions ...done.
Starting VirtualBox Guest Addition service mountall: Plymouth command failed mountall: Disconnected from Plymouth
...done. saned disabled; edit /etc/default/saned

blah blah blah

nothings starts up

Please help!

[noteirak]

Does it actually prevent your ubuntu installation from starting? or does it simply fail but you are able to continue?
If it just fails, all you need to do is update the extensions pack & guest additions to match your VBox version.