How to fix Synology’s Blue Led of Death

Today, after trying to update one of the applications of my NAS, a Synology 411J, I noticed that it became non responsive and upon rebooting, the dreaded flashing led of death came up.In order to avoid losing your content the following are the steps I followed in order to restore the NAS to its working order.

To recover the NAS, you will need

  • a spare hard disk you can use to reinstall the NAS (any density);
  • the latest version of the DSM for your device;
  • the latest version of the Synology Assistant software

(the latest 2 you will be able to download directly from Synology Support Page)

  1. Turn off the NAS. Open it and mark the hard disks so to remember their exact order.
  2. Insert your spare disk into the slot #1 and then turn on the NAS.
  3. Use the Synology Assistant to find your NAS on your network
  4. Reinstall the DSM from scratch (it will erase your spare hard disk)
  5. Upon completion of the the installation, shut down the device from the control panel.
  6. Reinstall the old hard disk in the same exact order and turn on.
  7. Reopen the Synology Assistant to find out the NAS once again. You will notice that the system is marked as “Migratable”.
  8. Install once again the NAS DSM file you installed (same of step 4). This time however only the DSM will be installed and all the data will be preserved.
  9. Wait about 10 minutes for the whole process to be completed.

Voila! Your NAS is back again in operation.


  1. Igmar Rautenbach

    Hi Nello,

    I have the same issue and want to follow your advice. But I struggle to find the NAS on network, or to log into in through the url,

    Any ideas?

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