There are LED indicators on the front panel of the DNS-323. Ifthe hard drive LED shows amber light (instead of green) the DNS-323has problems accessing that hard drive. Power OFF then ON theDNS-323 and leave it ON for a minute to check for changes on theLED colour.
If the LED still shows amber light, access the DNS-323management (web GUI) from your web browser. In TOOLS -DISKUTILTIES, scan the disk with the Fix option checked. Letutility run and read the results carefully. In STATUS -DEVICE INFO, check information about your hard drivesand observe the temperature. If the temperature is too high,make sure the fan on the back is not blocked, has stopped.
If you still cannot access the data on the disk, and the LEDshows amber light, the DNS-323 cannot recover the data. Power offthe DNS-323 and eject the disk (with the help from the lever on theback). Check for improvements if hard drive is inserted in theother drive bay.