
- Why Regular Data Recovery Tools Can’t Restore Files from RAID
- Key Information About the NAS Buffalo TeraStation WS5420DN16S9
- How to Remove Hard Disks from Your NAS and Connect Them to a PC
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 Buffalo 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 improper network configuration or firewall settings result in data loss on NAS Buffalo TeraStation WS5420DN16S9 devices?
Improper network configuration or firewall settings can potentially lead to data loss on NAS Buffalo TeraStation WS5420DN16S9 devices. Here are a few scenarios where this could occur:
- Network misconfiguration: If the NAS device is not properly configured to connect to the network or if there are issues with network settings such as IP address conflicts, subnet mismatches, or DNS configuration problems, it may result in connectivity issues or intermittent connection drops. These connectivity problems can lead to data loss if files are being transferred or accessed during these periods.
- Firewall blocking necessary ports: Firewalls can be configured to block specific ports or protocols that are required for NAS devices to function properly. If necessary ports (such as TCP port 445 for SMB file sharing) are blocked, it can prevent the NAS device from being accessed or files from being transferred, potentially leading to data loss.
- Inadequate firewall rules: If firewall rules are not properly configured to allow traffic between the NAS device and other network devices, it can cause connectivity issues or prevent data from being transferred. For example, if the NAS device needs to communicate with a backup server or a remote replication target, and the firewall is blocking this communication, it can result in data loss.
To mitigate these risks, it is important to ensure that the network configuration is set up correctly, the necessary ports are open on firewalls, and firewall rules are properly configured to allow the required traffic for NAS operations. Additionally, regular backups should be performed to minimize the impact of any potential data loss.
How to Remove Hard Disks from Your NAS and Connect Them to a PC
Although the NAS TeraStation WS5420DN16S9 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:
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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.
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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.
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Label each hard disk according to its position inside the NAS. The order of the drives is crucial for correct RAID reconstruction.
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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.
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Step-by-Step Data Recovery with Hetman RAID Recovery

This program restores data from damaged RAID arrays and is fully compatible with Buffalo TeraStation WS5420DN16S9. 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.
How to recover data from a Buffalo
TeraStation WS5420DN16S9 has 4 HDD slots, and it supports the following array types:
- RAID 0;
- RAID 1;
- RAID 5;
- RAID 6;
- JBOD;
NAS supports:
- exFAT, VFAT, FAT 12 / 16 / 32;
- NTFS / ReFS;
- APFS / HFS+;
- Ext2 / 3 / 4 / ReiserFS / XFS / UFS / ZFS / Btrfs;
- VMFS / HikvisionFS;
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:
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Ensure you have enough free space to store the image. Its size will typically match the size of the original disk.
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In the main window, select the target disk and choose Tools - Save Disk. You can also select multiple disks if needed.
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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.

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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.

Where Are the User’s Files Actually Stored?
The Buffalo TeraStation WS5420DN16S9 network-attached storage keeps Windows Storage Server 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 |


It is possible to recover data from a physically damaged NAS device, but the success of the recovery depends on the extent of the damage. If the internal components like hard drives or circuit boards are damaged, it may be more challenging to recover the data.
In such cases, it is recommended to contact a professional data recovery service that specializes in NAS devices. They have the expertise and tools required to recover data from physically damaged storage devices. However, it is important to note that data recovery can be a complex and expensive process, and there is no guarantee of success.