This article will guide you through troubleshooting steps if you see the status "Configuration lost" on Synology Assistant and cannot connect to your Synology NAS.

This issue may be a result of the following situations:

• The HDDs were moved from a NAS in a model pairing not recommended by Synology
• The system partition of the drives in your Synology NAS has failed
• The RESET button on your Synology NAS has malfunctioned
• The Synology NAS was accidentally reset using a Mode 2 Reset

When Synology Assistant displays the status "Configuration lost", double-clicking on your NAS will prompt you to reinstall DSM. Please follow the steps below to determine the root cause of the problem before taking any further action.

If your HDDs were moved from a NAS in a model pairing not recommended by Synology:

If the drives on this Synology NAS were recently migrated from another Synology NAS and you encounter the "Configuration lost" status, refer to this table to see if the pairing of the original NAS and this NAS is marked as "X". If so, this indicates that Synology does not recommend moving HDDs from your original NAS to this NAS. If you still wish to proceed with migration, double-click on your device in Synology Assistant and re-install DSM. DSM will be freshly installed after migration is completed. However, the user data in the volumes will remain intact.

To determine if the system partition of the drives has failed:¹

Try either of the following to solve the issue:

• To determine whether the partition failure is due to damaged drives, power off your Synology NAS, remove the drives and check the drives' health on your computer.²
• You may also insert a healthy spare drive into the first slot, install DSM, and then shut down the NAS. Re-insert the original drives back in their original order starting from the second slot, and turn on the NAS again. The healthy spare drive does not need to be removed from the first slot. Refer to this tutorial to check the health of your original drives. If there are issues with the original drives, please back up the data on your original drives immediately via File Station.

To determine if the RESET button has malfunctioned:

If the drives are healthy, but you continue to see the status, the problem could be a malfunctioning RESET button on the Synology NAS. Shut down your NAS, and thoroughly clean and dust off the device. Turn on your NAS and check if you still continue to see the status. If so, this indicates that the RESET button has malfunctioned. You can refer to this article for information on warranty policies. Synology does not provide direct replacement services outside North America; please contact the local reseller or distributor where you purchased the product for further assistance.

Your NAS was accidentally reset using a Mode 2 Reset:

Please refer to this article (for DSM 6.2.4 or above) or this article (for DSM 6.2.3 or earlier) for more information on how to reset your NAS.