In Acronis Backup 12.5 you can clone basic disks using bootable rescue media. Disk cloning in GUI is available only on Linux-based bootable media and only allows cloning basic MBR disks.
For more information on creating Acronis Bootable media, see Acronis Backup 12.5: how to create a bootable media. Remember to specify a serial number during bootable media creation, otherwise disk management will not be available.
Clone an active Windows system directly to a new drive without stopping your system and restarting Windows. This can be easily done with Acronis True Image and its Active Cloning feature.
If you want to clone a disk on Mac, see this article for instructions.