From the knowledge base, the relevant information is:
- A blinking blue Power LED means the unit is booting up / shutting down on DS416 and DS1019+; on older RS-406/CS-406e guides it also indicates system boot-up / shutdown.
- If the Power LED keeps blinking and the system never reaches solid status, the knowledge base suggests:
1. Check the health of your drives by trying to boot with a spare drive to see whether the issue persists.
2. Check attached external devices: power off the system, attach external devices one at a time, power on, and see whether the Power LED still keeps blinking for more than 20 minutes.
3. For some models, perform an internal check:
- unplug the power cord(s)
- remove any installed extended memory and PCIe card
- confirm the motherboard is properly installed and is Synology-manufactured
- clean and reinstall the memory modules
4. If the issue remains unresolved, contact Synology Technical Support or the local reseller/distributor.
The knowledge base does not provide a more specific fix for your exact model beyond these troubleshooting steps.
Sources used: [1], [9], [12]