Hi,
I tried updating to version 14 and I get the same error. The OS under 'Edit Settings > VM Options' is 'CentOS 7 (64-bit)'. I tried unregistering/registering and changing the the OS to 'CentOS 6 (64bit)', saved it, then changed it back to 'CentOS 7 (64bit)' and it still gave me that error!
Alex