after security update on 09 mar 2012, 11.10 has fatal modprobe on 3.0.0-16-generic

Can you expand on "fails", it tells us very little....

Where 3.0.0-16 gets beyond the boot screen:
6 messages:
modprobe:FATAL; /lib/modules/3.0.0-16-generic/modules.dep Could not load: No such file or directory

In the case of failure immediately following the boot screen, all disc activity stops within 1 second of choosing the boot option.

After booting 3.0.0-15, a check on /lib/modules shows that /lib/modules/3.0.0-16-generic/modules.dep does exist.

hold shift and boot to recovery mode then select root. then run:

depmod -a; reboot

should now be ok

While holding SHIFT and looking for 'boot to recovery', boot occurred anyway, and succesfully. I checked with another boot to the default 3.0.0-16-generic, and all was well.

The only thing changed in the meantime was an update of Cinnamon from 1.2 to 1.3.1. Maybe 3.0.0-16-generic is incompatible with cinnamon 1.2?

Many thanks anyway. Please close this issue.

Cinammon is a 3rd party app, so maybe. Cinnamon is not supported by the official Ubuntu channels.

You are the only one whom can mark this as solved, which you have done :)