Practical Steps to Extract Data from a RAID Disk if NAS TerraMaster U16-420 Does Not Boot

Has your NAS TerraMaster U16-420 suddenly lost its network drive and you’re unsure what to do next? Did the RAID array collapse, making your files inaccessible? Is the device throwing errors during startup? Perhaps you accidentally rebuilt the RAID array or several hard drives failed at the same time?

Practical Steps to Extract Data from a RAID Disk if NAS TerraMaster U16-420 Does Not Boot
Data Recovery Tool

TerraMaster U16-420 NAS Data Recovery in 2025

In this step-by-step tutorial, we’ll show you how to rebuild your RAID and recover data from an U16-420. We’ll walk through the most common causes of failure and demonstrate proven methods to restore files from a lost or degraded RAID array.

Practical Steps to Extract Data from a RAID Disk if NAS TerraMaster U16-420 Does Not Boot

RAID Recovery™ 2.8
Recover data from damaged RAID arrays inaccessible from a computer.
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Why Regular Data Recovery Tools Can’t Restore Files from RAID

Conventional hard drives store user data by writing it sequentially across the disk surface, which means an entire file is typically located on a single drive. In contrast, when data is written to a RAID array, each file is split into multiple fragments. These fragments are then distributed and written in sequence across all the drives in the array. Depending on the configuration, fragment sizes can range from 2 KB to 2 MB, so every file is physically stored across several disks at once.

This approach significantly increases read and write performance — after all, writing two halves of a 1 GB file to two drives simultaneously is much faster than writing the full 1 GB to a single disk. However, this same mechanism makes file recovery far more complex.

Different RAID levels use different methods to distribute and protect data. On top of that, manufacturers like TerraMaster often add their own proprietary structures and variations. As a result, data can be written to disks in many different formats, and each requires a specific approach during recovery.

Can the use of deduplication or compression technologies impact data loss risks on NAS TerraMaster U16-420 devices?

The use of deduplication or compression technologies can potentially impact data loss risks on NAS TerraMaster U16-420 devices. Here's how:

  1. Deduplication: Deduplication technology eliminates redundant data by storing only unique data blocks and creating references to them. While this can save storage space, it introduces a risk of data loss. If a single unique data block is corrupted or lost, it can affect multiple files or data sets that reference that block. Therefore, if deduplication is enabled on a TerraMaster U16-420 device, the risk of data loss increases as the integrity of each unique data block becomes crucial.
  2. Compression: Compression technology reduces the size of files or data sets by encoding them in a more efficient format. While compression can save storage space, it also increases the risk of data loss. If the compressed data becomes corrupted or lost, it may not be possible to recover the original uncompressed data. Therefore, if compression is used on a TerraMaster U16-420 device, there is a higher risk of data loss compared to uncompressed data.

It's important to note that the impact of deduplication or compression technologies on data loss risks depends on various factors such as the implementation, reliability of the underlying storage system, and backup strategies in place. It's recommended to thoroughly evaluate the capabilities and limitations of these technologies and consider implementing proper backup and redundancy measures to mitigate data loss risks.

How to Remove Hard Disks from Your NAS and Connect Them to a PC

Although the NAS U16-420 can be accessed over the network, you still need to remove its hard disks and connect them directly to a Windows PC. Only then can the recovery software properly scan and analyze the drives. Follow these steps:

  1. Power off the NAS and disconnect it from the power source.

    WARNING! Before removing any drives, carefully read the device manual. Improper actions may damage both the NAS enclosure and the hard disks in the RAID array.

  2. Remove the hard disks one by one, gently sliding each drive out of its slot. Remember that hard disks are highly sensitive: any impact or drop can cause serious physical damage.

  3. Label each hard disk according to its position inside the NAS. The order of the drives is crucial for correct RAID reconstruction.

  4. Connect the drives to your computer. In this video, we explain which ports you can use to connect hard disks and what to do if your PC does not have enough free connectors.

    Go to view
    How to Order Remote Data Recovery

    How to Order Remote Data Recovery

Step-by-Step Data Recovery with Hetman RAID Recovery

Hetman Raid Recovery

This program restores data from damaged RAID arrays and is fully compatible with TerraMaster U16-420. Each hard disk in the array contains technical metadata describing how files were written. When launched, Hetman RAID Recovery analyzes this metadata, automatically reconstructs the damaged array, and provides access to its contents. After that, you can browse the recovered disk and save your files. The program can also restore files that were accidentally deleted from the network drive.

Go to view
How to recover data from a TerraMaster

How to recover data from a TerraMaster

U16-420 has 16 HDD slots, and it supports the following array types:

  • RAID 0;
  • RAID 1;
  • RAID 5;
  • RAID 6;
  • RAID 50;
  • RAID 60;
  • JBOD;

NAS supports:

  • Ext2;
  • Ext3;
  • Ext4;
  • Btrfs;

How to Safely Recover Data from Disk Images

This utility allows you to create a complete copy of a disk and work with the disk image instead of the physical drive. This approach helps protect your data from:

  • Overwriting during the recovery process;
  • Additional data loss caused by bad sectors;
  • User errors.

To create a disk image, follow these steps:

  1. Ensure you have enough free space to store the image. Its size will typically match the size of the original disk.

  2. In the main window, select the target disk and choose Tools - Save Disk. You can also select multiple disks if needed.

  3. When the Image Creation Wizard opens, select whether you want to save the entire disk or only a specific region. Adjust the settings and click Next.

    Hetman RAID Recovery: Image Creation Wizard

  4. Choose the directory where the image will be saved. You may select any available disk connected to your PC or upload the image via FTP.

    Hetman RAID Recovery: Choose a disk or save the image via FTP

Where Are the User’s Files Actually Stored?

The TerraMaster U16-420 network-attached storage keeps OS Linux operating system files on a separate RAID 1 (mirrored) array. Usually, all NAS systems create several volumes on every hard disk, and the first of them takes up to 2 Gb of space. This is where operating system files are stored. Other volumes are united into a RAID array where user’s data is written.

RAID Recovery Software: Detailed Comparison

Product Operating system RAID controller support Supported file systems Virtual RAID controller support Data recovery from damaged RAID File preview
Hetman RAID Recovery Windows, Linux, MacOS Yes, over 100 controllers FAT, exFAT, NTFS, ReFS, APFS, HFS+, Ext4, Ext3, Ext2, ReiserFS, Btrfs, VMFS, Hikvision, XFS, UFS, ZFS Yes Yes Yes
DiskInternals RAID Recovery Windows Yes, over 10 controllers FAT, NTFS, Ext2/3/4, HFS+ No Yes Yes
R-Studio Windows, Mac, Linux Yes, over 20 controllers FAT, NTFS, Ext2/3/4, HFS+ Yes Yes Yes
UFS Explorer RAID Recovery Windows, Mac, Linux Yes, over 100 controllers FAT, NTFS, Ext2/3/4, HFS+ Yes Yes Yes
EaseUS Data Recovery Windows Yes, over 20 controllers FAT, NTFS, Ext2/3/4, HFS+ No Yes Yes
ReclaiMe Free RAID Recovery Windows Yes, over 100 controllers FAT, NTFS, Ext2/3/4, HFS+ Yes Yes Yes

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Comments (3)

  • Hetman Software: Data Recovery
    Hetman Software: Data Recovery 9.08.2022 12:31 #
    If you want to ask a question about data recovery, from NAS U16-420, feel free to leave a comment!
    Reply
  • Will Manly
    Will Manly 10.09.2023 05:45 #
    Are there any specific backup software recommended for data recovery from NAS TerraMaster U16-420 devices?
    Reply
    • Hetman Software
      Hetman Software 10.09.2023 05:59 #

      There are several backup software options that you can consider for data recovery from NAS TerraMaster U16-420 devices. Here are a few popular ones:

      1. Acronis True Image: Acronis True Image is a comprehensive backup and recovery software that supports NAS devices, including TerraMaster U16-420. It offers features like full image backups, file-level backups, and easy recovery options.
      2. Synology Active Backup: Synology Active Backup is designed specifically for Synology NAS devices, but it can also work with other NAS brands like TerraMaster. It provides efficient backup and recovery solutions, including features like deduplication and incremental backups.
      3. Veeam Backup & Replication: Veeam Backup & Replication is a powerful backup software that supports a wide range of storage devices, including NAS systems. It offers features like instant VM recovery, granular file-level recovery, and replication for disaster recovery.
      4. NovaBACKUP: NovaBACKUP is a user-friendly backup software that supports NAS devices, including TerraMaster U16-420. It provides features like file-level backups, disk imaging, and flexible recovery options.
      5. EaseUS Todo Backup: EaseUS Todo Backup is a popular backup software that supports NAS devices, including TerraMaster U16-420. It offers features like system backup, disk/partition backup, and file-level backup, along with easy recovery options.

      Remember to choose a backup software that suits your specific requirements and offers compatibility with TerraMaster U16-420. It's also recommended to check the software's documentation and compatibility list to ensure it supports your NAS device.

      Reply
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Vladimir Artiukh

Author: Vladimir Artiukh, Technical Writer

Vladimir Artiukh is a technical writer for Hetman Software, as well as the voice and face of their English-speaking YouTube channel, Hetman Software: Data Recovery for Windows. He handles tutorials, how-tos, and detailed reviews on how the company’s tools work with all kinds of data storage devices.

Oleg Afonin

Editor: Oleg Afonin, Technical Writer

Oleg Afonin is an expert in mobile forensics, data recovery and computer systems. He often attends large data security conferences, and writes several blogs for such resources as xaker.ru, Elcomsoft and Habr. In addition to his online activities, Oleg’s articles are also published in professional magazines. Also, Oleg Afonin is the co-author of a well-known book, Mobile Forensics - Advanced Investigative Strategies.

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Questions and answers

  • What are the steps to access files on the NAS TerraMaster U16-420 from a remote location?

    To access files on the NAS TerraMaster U16-420 from a remote location, follow these steps:

    1. Ensure that the NAS TerraMaster U16-420 is connected to the internet and has a valid IP address.
    2. Configure port forwarding on your router to allow remote access to the NAS. This step may require accessing your router's settings and forwarding the appropriate ports (usually TCP port 80 for HTTP access and TCP port 443 for HTTPS access) to the IP address of the NAS.
    3. Set up a dynamic DNS (DDNS) service if your internet connection has a dynamic IP address. This service will assign a domain name to your NAS, which will remain accessible even if your IP address changes. Some NAS devices have built-in DDNS support, or you can use a third-party DDNS provider.
    4. Enable remote access on the NAS TerraMaster U16-420. This step usually involves accessing the NAS's web interface through a web browser and navigating to the remote access settings. Enable any necessary features like FTP, WebDAV, or SMB/CIFS.
    5. Configure user accounts and permissions for remote access. Create user accounts on the NAS and assign appropriate permissions to each user, ensuring that they have access to the files and folders you want to share remotely.
    6. Set up secure remote access. If you want to access your files securely, consider enabling SSL/TLS encryption and configuring a secure connection using HTTPS or FTPS.
    7. Test the remote access. From a different network or location, open a web browser and enter the DDNS domain name or your public IP address followed by the appropriate port number (e.g., http://yourdomain.com:80 or https://yourdomain.com:443). If everything is set up correctly, you should be able to log in and access your files remotely.

    Note: The specific steps may vary depending on the NAS device and its firmware version. It's recommended to consult the user manual or manufacturer's documentation for detailed instructions tailored to your NAS model.

  • What are the security measures or protocols in place to ensure safe file access from a remote location on the NAS TerraMaster U16-420?

    The TerraMaster U16-420 NAS device incorporates several security measures and protocols to ensure safe file access from a remote location. Some of these measures include:

    1. User Authentication: The NAS supports various user authentication methods, such as local user accounts, Active Directory, LDAP, and more. These authentication methods ensure that only authorized users can access the files remotely.
    2. SSL/TLS Encryption: The NAS utilizes SSL/TLS protocols to encrypt the communication between the remote client and the NAS device. This encryption ensures that the data transmitted over the network remains secure and protected from eavesdropping or tampering.
    3. VPN Support: The TerraMaster U16-420 supports Virtual Private Network (VPN) connections. By setting up a VPN tunnel, remote users can securely access the NAS as if they were directly connected to the local network. VPNs provide an additional layer of security by encrypting the entire communication between the remote client and the NAS.
    4. Firewall and IP Access Control: The NAS device has a built-in firewall that can be configured to restrict access from unauthorized IP addresses or IP ranges. This helps prevent unauthorized access attempts and protects the NAS from malicious activities.
    5. Two-Factor Authentication (2FA): TerraMaster U16-420 supports two-factor authentication, which adds an extra layer of security by requiring users to provide a second form of authentication, such as a verification code generated by a mobile app, in addition to their password.
    6. File-Level Access Control: The NAS offers granular file-level access control, allowing administrators to define specific access permissions for individual users or user groups. This ensures that users can only access the files they are authorized to access, reducing the risk of unauthorized data exposure.
    7. Audit Logs and Alerts: The NAS keeps detailed audit logs of user activities, including file access, modifications, and system events. Administrators can review these logs to monitor any suspicious activities and take appropriate actions. The NAS can also send alerts or notifications to administrators in case of any security-related events or anomalies.

    It's important to note that while the TerraMaster U16-420 implements these security measures, it is crucial for administrators to properly configure and regularly update the NAS firmware and software to maintain a secure environment.

  • Are there any limitations or restrictions when accessing files on the NAS TerraMaster U16-420 from a remote location, such as file size limits or network speed considerations?

    When accessing files on the NAS TerraMaster U16-420 from a remote location, there are a few limitations and restrictions to consider, including:

    1. Network Speed: The speed of your internet connection will impact the file transfer speed. Slower internet connections may result in slower transfer speeds.
    2. Bandwidth: If multiple users are accessing the NAS remotely, the available bandwidth may be divided among them, potentially affecting transfer speeds.
    3. File Size Limits: The NAS TerraMaster U16-420 typically supports large file sizes, but there may be limitations imposed by the file system or the remote access software you are using. For example, some file systems have a maximum file size limit of 4GB or 16TB.
    4. Connection Stability: The stability of your internet connection can affect the reliability of file transfers. If the connection drops frequently or is unstable, it may interrupt or slow down file transfers.
    5. Security and Access Control: When accessing files remotely, it is important to consider security measures. Ensure that you have appropriate access control settings, such as strong passwords and encryption, to protect your data from unauthorized access.

    It is recommended to check the user manual or contact the TerraMaster support team for specific details and limitations related to the NAS TerraMaster U16-420.
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