[Solution] Recover Data from Synology RAID Set That Is Broken or Crashed

  • Written By Jyoti Prakash

  • Updated on February 12, 2021

  • Min Reading 6 Min

Summary: A degraded, broken, or crashed Synology RAID is a critical situation that can lead to permanent data loss. But with prompt action, you may rebuild or reconstruct a corrupt RAID and get access to your data. In this guide, you will learn how to fix and recover lost data from a broken or crashed Synology RAID NAS safely with Stellar Data Recovery Technician software.

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A Synology RAID set or Network Attached Storage (NAS) may degrade, fail, crash, break or corrupt anytime due to mechanical, physical and logical disk errors caused by virus or malware infection, corrupt system files, sudden power loss, damaged device drivers, force shutdown, improper handling or storage, bad sectors, etc.

While popular Synology RAID sets such as RAID 1, RAID 5, and RAID 6 can withstand up to one to two disk failures, these RAIDs can’t withstand multiple disk failure and corruption due to logical errors and system crash.

When a RAID set breaks or crashes, you are generally left with only one option and, i.e., RAID data recovery.  

When we talk about Synology RAID recovery, there are only a few options, which are as follow,

  1. Mdadm in Ubuntu
  2. Stellar Data Recovery Technician for Windows

But before you proceed with Synology RAID data recovery steps, here are some notable pros and cons of each option,

1. Mdadm for Ubuntu


  • Free


  • Complicated for users without knowledge of Linux / users not comfortable with the command line
    • Synology’s FAQ doesn’t cover all possible scenarios
    • Requires a RAID hardware controller

2. Stellar Data Recovery Technician for Windows


  • Highly intuitive and easy to use Windows RAID data recovery utility
    • Requires minimal efforts and ideal for newbies as well as professionals and power users
    • Does not require a hardware RAID controller
    • Reconstructs broken and crashed RAID even if parameters are unknown or not provided
    • Features video and photo repair modules and a Disk Monitor utility that assists in secure data recovery from broken or crashed RAID 0, RAID 5, and RAID 6 arrays
    • Facilitates disk cloning, comes handy when RAID drives are failing due to SMART or other logical errors 


  • A licensed version of Stellar Data Recovery Technician costs a few bucks to save the important data from the free preview window.

Now that you know about all three possible options to recover data from a broken or crashed Synology RAID set, follow the steps given below to get back your lost files.

Steps to Recover Data from Broken or Crashed Synology NAS based on RAID 0, RAID 5, or RAID 6 Array

Since Ubuntu way is complicated, we will detail the Stellar® way to recover data from broken or crashed Synology RAID. It’s much easier and safe as the software handles all the complicated tasks in the back-end. Get the software now!

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Step 1: Disconnect RAID Drives

  • Remove all Drives from the broken or crashed Synology RAID set and connect them to a working Windows PC via SATA connectors.
  • Alternatively, you may use SATA to USB converter cables or enclosures to connect Synology RAID drives to Windows PC or laptop

Step 2: Inspect RAID Drives’ Health and SMART Status

  • Download, install, and launch Stellar Data recovery software and click the Waffle icon at the top right and choose ‘Monitor Drive.

Alternatively, you may also use CrystalDiskInfo or similar SMART disk utility. But Drive Monitor displays more detailed information about the disk health, performance and SMART status besides an option to clone disk.

  • Check the hard drive health. If the utility displays SMART warning or any health or performance-related warning signs, immediately clone the disk

Disk cloning is important as any further rigorous data recovery scan and actions can cause drive failure, leading to permanent data loss.

Step 3: Clone Disk [Optional]

NOTE: This drive cloning is optional but highly recommended for safe data recovery from failing RAID drives

  • Connect a new or healthy hard drive with volume size equal or larger than the affected RAID drive
  • Click ‘Clone Disk’ and choose the source (affected drive) and target disk (new or healthy drive) from respective drop-downs
  • Click ‘Clone’ and click ‘Start’ to accept and begin the cloning process
  • Wait for the cloning process to finish. Repeat the steps for other degraded RAID drives

After the clone, replace the degraded RAID drive with a newly cloned hard drive and proceed to the next step to perform effortless data recovery from connected RAID drives.

Step 4: Reconstruct Broken or Crashed Synology RAID Array

To reconstruct a Synology RAID 0, RAID 5, or RAID 6 set, close the ‘Drive Monitor’ utility (if running) and launch the Stellar Data recovery Technician tool.

  • Then choose what file types you want to recover and click ‘Next.

TIP: You can add a custom or uncommon file format in the supported file list for data recovery. The ‘Add Header’ option in Settings allows you to add unlimited file formats and enables users to recover virtually any file type.

  • Choose ‘RAID Recovery’ under Other Locations and click ‘Scan.
  • Click on the RAID tab—RAID 0, RAID 5, or RAID 6. All Synology RAID disks connected to the system are visible under ‘Select Hard drives to reconstruct RAID’ list box.
  • Click on a disk and use the arrow button to add or remove RAID drives from the ‘Select Hard drives to Reconstruct RAID’ list box to ‘Move hard drives up/down for disk order’ list box. Repeat the step to move all RAID disks.
  • Use the up and down arrow buttons adjacent to the list view box to arrange drives in the right sequence as they were in the Synology RAID set.
  • Enter or select all the required RAID parameter values and click ‘Build RAID.’

TIP: Choose the ‘Don’t know…..’ option if you don’t know the required RAID parameters. When parameters are not provided, the software intelligently constructs probable virtual RAID array(s)

  • Wait until the software reconstructs your RAID volume or probable RAID volumes.
  • After RAID reconstruction, choose the RAID volume from the list and click the ‘Scan’ button.
  • After the scan, if the desired files are not found in the scan results, click the ‘Click Here’ link at the bottom to begin ‘Deep’ Scan.
  • Post deep or quick scan; you can click on a file to see its preview or choose the files and folders that you want to recover.
  • Then click ‘Recover’ and then ‘Browse’ to select a save location—where you want to save the recovered data.

NOTE: Never choose the affected RAID drive(s) (source drive). Use an external USB drive or internal disk volume with enough storage space to save recovered data. In case your system is running low on storage, save the scan information to recover data in stages.

  • Finally, click the ‘Start Saving’ button. The selected recovered files and folders will be saved at your desired location.

Now that you have access to your lost data from broken or crashed Synology RAID, format each drive to construct RAID from scratch. And to avoid such data loss situations, always keep atleast two backup copies of all your important files.

Remember, RAID is not a backup or an alternative to backups!


Synology NAS based on RAID arrays may break or crash due to disk failure caused by logical, mechanical, or physical errors. Often, it occurs due to logical errors such as file system errors, virus or malware infection, abrupt shutdown, device driver issues, etc.

You can use mdadm commands to resync the RAID array for data recovery. But mdadm works in Ubuntu. If you aren’t familiar with Ubuntu or Linux command line, leverage a powerful RAID data recovery software such as Stellar® Data Recovery Technician for Windows.

The latter method is much easier and doesn’t require any specialized skills. If you are familiar with Windows, you can use Stellar® Data Recovery Technician to recover data from a broken, crashed, degraded, or corrupt RAID 0, RAID 5, and RAID 6 array.

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