Connect to Unformatted Hard Disk

1. Turn OFF power to E4K and SCSI device.
2. Connect via SCSI cable.
3. Set SCSI ID of device to a number other than 6.
4. Turn on devices.
5. Press Disk button. Select Format under Utils (F1, F3).
6. Press OK to format.

Source: E4K — e-mu-emulator-4k-manual (manual)