What types of hard drive can I use for Initial Seeding?

Only USB hard disk drives. Use your own device or buy a 1 TB or 2 TB device from Acronis along with the Initial Seeding license. You can back up directly to the USB device or back up to a local or network folder and then copy the backup to the USB device. Make sure that the device has only one volume, and that the file system on that volume is NTFS or FAT32.