Solved FreeBSD 10.1 error please help me

Hello , After reboot I get this error and it does not recover without reset.

CAM is the low-level storage interface. The error basically means that the system can't interface with the disk. I would guess that your virtual disk file is corrupted.
There's not enough info to go on here. Did you by any chance compile your own kernel or change anything else on the system before rebooting? Because if you did then I'd be more tempted to look for the cause of the problems there. If so then you can try to boot with a backup kernel.