After installing 15.10 on my yoga everything seemed to work fine. But after some reboots i got this message.
I found this report: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1492764
Saying "it disappeared with 4.3.0-040300rc3-generic."
But i cannot start X any more to start the internet connection and download the new kernel.
Is there a workaround to get an X running to fix this?