A Hard Drive is not detected error message indicates a hard disk drive (HDD) issue within your DVR / NVR system. To resolve the error, reseat your HDD to ensure the cable connections are secure.
To reseat your HDD:
Power off the DVR / NVR system and unplug all cables.
WARNING: Make sure that the system is off and the power cable is disconnected before attempting to open your DVR / NVR.
The DVR / NVR cover is secured with screws. Remove the screws and slide the cover off.
WARNING: The inner casing of the DVR / NVR has sharp edges that can lead to injury if not carefully handled. Be careful not to let any tools or loose parts touch sensitive components such as the circuit board.
Disconnect and reconnect the two cables going to the HDD. Make sure they are securely connected.
Carefully replace the casing of the DVR / NVR and secure the screws.
Reconnect the power source and monitor.
Right-click on the DVR / NVR Live View to access the Quick Menu.
Click Main Menu and then click the Setting icon ().
Click Storage > HDD Manager.
The DVR / NVR HDD Manager should now detect the HDD and the error message should be resolved.