You cannot access your Synology NAS even though the Power LED indicator is normal. Drive failures or other issues may cause  system partition errors and make your Synology NAS inaccessible. If the Power LED indicator keeps blinking, refer to this article.

Check the power and connection of your Synology NAS

1. Power off your NAS and remove all the drives from your NAS..
2. Power on your NAS and make sure the connection is normal before proceeding with the following steps.

Recover your data

Follow the instructions that best suit your situation:

For one-bay models:

Use a PC to recover your data.

For multi-bay models:

1. Follow the steps in this article. If these steps do not work for you, proceed to the steps below.
2. Make sure the RAID type of your storage pool is with data protection and offers data redundancy. These RAID types include RAID 1, RAID 5, RAID 6, RAID 10, RAID F1, and SHR consisting of at least two drives.
   • If the RAID type of your storage pool is without data protection (i.e., Basic, JBOD, RAID 0, or SHR consisting of only one drive), make sure at least one empty drive slot is available on your Synology NAS before you proceed to the next step. If there are no drive slots available, use a PC to recover your data.
3. Power off your NAS and remove all drives.
4. Install a spare drive in the location of Drive 1 before powering on you NAS.
5. Install DSM on the spare drive and test if you can access it. The DSM version must be the same version as that on your NAS.
   Do NOT use the spare drive to create storage pools or volumes.
6. Power off your NAS and insert any of the original drives back to your NAS, but keep the spare drive in Drive 1.
7. Power on your NAS and do the following according to your DSM version:
   • DSM 7.0 and above:
     1. Go to Storage Manager > Overview or Storage.
     2. Click the Online Assemble link (if available) to assemble your storage pool or volume and recover your data.¹
   • DSM 6.2 and below:
     1. Go to Storage Manager to check if your volume is available.
     2. Go to File Station to check if you can access your files.
     3. Go to Storage Manager > Overview and click the repair link to repair the system partition.²
8. Use the spare drive or replace it with a new drive to repair the degraded storage pool. For detailed instructions, refer to the articles for DSM 7 or DSM 6.2.

Check the drive status

1. Go to Storage Manager > HDD/SSD.
2. Check the drive or health status. If the status is not Healthy, the drive may be defective and needs to be replaced. ^{3 4}