This problem may occur due to compatibility issues with the drive(s), or as a result of not having the applicable option(s) enabled in BootIt NG's settings.
Please note that SCSI CD drives are not supported via the SCSI controller. Instead, connect an ATAPI CD drive to an IDE controller.
For USB, the controller and external case must be USB 2.0 and the USB 2.0 Support option must be enabled in BootIt NG's settings. For IEEE 1394 drives, be sure to enable the IEEE1394 Support option.
If the problem occurs with a USB drive even with the USB 2.0 Support option enabled in BootIt NG, you may want to try disabling the Legacy USB Support option in the system BIOS (some systems may refer to this option as USB BIOS Support).
Please also refer to the article titled USB 2/IEEE 1394 Device Does Not Appear in Partition Work.