vmx connection handshake failed for mks of vmfs

This error message indicates that your VM didn't start properly and was powered off. This typically happens if your VM is trying to start in 64 bit mode, but it has been configured as a 32 bit VM or if you're booting from a corrupt .iso file.

If you look in the log file of the VM you will see a message similar to this one:

Jul 01 12:21:30.093: vcpu-0| MonitorInitReserveMem64: vmm64OverheadPages=5156
Jul 01 12:21:30.095: vcpu-0| Could not reserve memory for vmm64. Are you sure your VM specifies a 64 bit guest OS type?

In the above case, changing the VM type to a 64 bit OS fixes the error.