LED
Status
Description
Drive
Flashes red
The data is being accessed and a read/write error occurs
during the process.
Red
• A drive read/write error occurred.
• The drive temperature is over the threshold.
Flashes green
• Data is being accessed.
• Data is being copied.
Green
• The drive can be accessed.
• The device is powered on.
Off
No drive is detected.
M.2 SSD
Flashes red
The drive is being located.
Red
A drive read/write error has occurred.
Flashes green
The data is being accessed.
Green
The drive can be accessed.
Off
No drive is detected.
USB Expansion
Unit
Blue
A QNAP USB external storage device is connected to a
USB port.
Off
No USB external storage devices connected.
Audio Alert
Duration
Frequency
Description
Short beep (0.5 seconds) 1
• The NAS is starting up.
• The NAS is shutting down (software shutdown).
• The user pressed the Reset button.
• The operating system was updated.
3
The user tried to copy the NAS data to the external
storage device from the front USB port, but the data
cannot be copied.
Long beep (1.5 seconds) 3 (every 5 minutes)
The system fan is not functioning.
2
• The disk volume is about to reach its full
capacity.
• The disk volume has reached its full capacity.
• The drives are in degraded mode.
• The user started the drive rebuilding process.
• A drive is plugged in or out.
1
• The NAS was powered off by force shutdown
(hardware shutdown).
• The NAS was powered on successfully and is
ready.
TS-451DeU User Guide
Basic Operations
35