Backup External Drives on WD NAS: Full Guide

Yes, you can back up external drives to a WD NAS (like My Cloud, My Cloud Home, or WD Pro/PR series) either by plugging the drive into the NAS’s USB port and using the built-in copy function, or by connecting the drive to your computer and copying over the network. The exact steps depend on your WD model and firmware, but the core process is straightforward and gives you a centralized, always-on copy of your data.

Why Back Up an External Drive to a NAS

An external drive is often the only copy of important files, and it is vulnerable to physical damage, loss, or theft. Moving the data to a NAS adds a second copy on a device that is designed to run 24/7, supports RAID redundancy on multi-bay models, and can be accessed from multiple devices on your network. It also frees up the external drive for other uses, or lets you retire an old drive that is showing signs of age.

For example, if you have a 2 TB USB drive full of family photos, copying it to a 4-bay WD NAS with two drives in RAID 1 means the photos survive a single drive failure. The NAS also gives you the option to set up automatic cloud backup to a service like Backblaze or Amazon S3, which the external drive alone cannot do.

What You Need to Know About WD NAS Models

WD sells several NAS lines, and the backup method differs:

My Cloud (single-bay, home models) – These have one USB port (USB 2.0 or 3.0) and run the My Cloud OS. They support a one-touch USB copy button on the back of the unit, and also a web-based “USB Storage” page where you can copy files to and from the attached drive.
My Cloud Home / Home Duo – These are consumer-focused, with a simplified interface (no admin web dashboard). They use the My Cloud Home mobile/desktop app, and you can import files from a USB drive plugged into the back. The app has an “Import from USB” option.
WD Pro/PR series (formerly My Cloud Expert, EX, DL, etc.) – These run the more advanced WD OS (based on a Linux distribution). They have a full admin dashboard with a “USB Storage” or “External Storage” section that lets you browse, copy, and schedule backups from the attached drive.

Check your model’s manual to confirm which interface you have. The steps below cover the two most common methods.

Method 1: Direct USB Copy on My Cloud (Classic)

This is the fastest method because it does not involve your computer or your network. It works on most My Cloud models (not the Home series).

Plug the external drive into the USB port on the back of the NAS. Wait for the LED to stop blinking (usually 10-30 seconds).
Log into the My Cloud web dashboard by typing the NAS IP address (e.g., http://192.168.1.10) into a browser.
Go to Storage > USB Storage. You should see your drive listed.
Select the files or folders you want to copy, then click Copy to and choose a destination folder on the NAS.
Alternatively, press the physical USB Copy button on the back of the NAS (if your model has one). This copies the entire contents of the USB drive to a default folder named USB Storage on the NAS.

This method is a one-time manual copy. It does not create a scheduled backup.

Method 2: Copy Over the Network from Your Computer

If your NAS does not have a USB port, or you prefer to keep the external drive connected to your computer, you can copy the files over the LAN.

Connect the external drive to your computer and make sure it is recognized.
Open File Explorer (Windows) or Finder (Mac).
In the address bar, type \\[NAS_IP] (Windows) or smb://[NAS_IP] (Mac). Enter your NAS username and password if prompted.
Navigate to the folder where you want the backup to live (e.g., Public or a shared folder you created).
Drag and drop the files from the external drive to the NAS folder. Use a tool like rsync (Mac/Linux) or robocopy (Windows) for a more reliable copy that can resume after interruptions.

This method is slower than direct USB because data goes through your network, but it works for any NAS and any external drive.

How to Schedule Automatic Backups

Manual copies are fine for one-time transfers, but for ongoing protection you want automation. On WD Pro/PR series NAS, you can set up a scheduled backup job:

Log into the admin dashboard.
Go to Backup > USB Backup (or External Backup).
Choose the source as the USB drive, the destination as a NAS folder.
Set a schedule (daily, weekly, at a specific time).
Enable the option to copy only new or changed files (incremental) to save time.

On My Cloud Home, you cannot schedule USB imports; you have to do it manually via the app. For a free alternative, you can use software on your computer (like FreeFileSync or rsync) to sync the external drive to a network share on the NAS on a timer.

Common Problems and Fixes

NAS does not recognize the USB drive – The drive may be formatted with a filesystem the NAS cannot read (e.g., NTFS works on most WD NAS, but exFAT may not on older models). Reformat the drive to NTFS (Windows) or HFS+ (Mac) if it is not already. Also try a different USB port or a powered USB hub if the drive is not getting enough power.
Copy fails halfway – This is usually due to a failing external drive or a file name that is too long. Use a tool like robocopy (Windows) with the /Z flag to resume, or rsync with --partial to keep partially copied files.
Files are corrupted after copy – Always verify the copy by comparing file sizes or checksums. On Windows, use fc /b; on Mac, use cmp. A mismatch means the source drive is failing or the network dropped data.
USB copy button does nothing – On My Cloud, the button only works if the drive is formatted with a supported filesystem and the NAS has finished booting. Try the web interface method instead.

Safety and Best Practices

Backing up to a NAS is not a complete backup strategy. The NAS itself can fail, be stolen, or be hit by ransomware. Follow the 3-2-1 rule: keep at least three copies of your data, on two different types of media, with one copy offsite. So, after copying your external drive to the NAS, also consider:

Keep the external drive as a second copy (do not erase it immediately).
Enable NAS-to-cloud backup (WD My Cloud has built-in support for Backblaze B2, Amazon S3, and others).
Set up RAID on a multi-bay NAS, but remember RAID is not a backup – it only protects against drive failure, not accidental deletion or corruption.

Alternatives to WD NAS for External Drive Backup

If you do not have a WD NAS, other options include:

Another external drive – Simple, but requires manual copying and is not always-on.
A cloud service – Google Drive, Dropbox, or Backblaze. Good for offsite, but you pay for storage and upload time.
A Raspberry Pi with a USB drive – A DIY NAS that is cheap but requires technical setup.
A different NAS brand – Synology and QNAP have similar USB copy features, often with more flexible scheduling.

Frequently Asked Questions

Can I plug a USB drive into My Cloud Home to back it up?

Yes, plug the drive into the USB port on the back, then open the My Cloud Home app on your phone or computer. Go to the drive’s folder and select “Import from USB.” You can choose which files to copy. It is a manual process; there is no automatic scheduling on Home models.

Does the USB copy button on My Cloud copy both ways?

No, the physical button only copies from the USB drive to the NAS. To copy from the NAS to the USB drive, you must use the web dashboard and drag files into the USB storage folder.

What filesystem should my external drive be?

For best compatibility, use NTFS (Windows) or HFS+ (Mac). exFAT works on newer WD NAS models but may not be supported on older ones. FAT32 works but has a 4 GB file size limit, which is a problem for large video files.

Can I back up a Time Machine drive to a WD NAS?

Yes, but not directly. Time Machine requires a network share formatted as HFS+ or APFS. Some WD NAS models support Time Machine over SMB. If yours does not, you can copy the Time Machine sparse bundle to the NAS, but it is not a true backup of the backup.

Is it safe to leave the external drive plugged in all the time?

Generally yes, but it will spin up and down, which can wear the drive over time. If you only need occasional backups, unplug it when not in use. For scheduled backups, leave it plugged in and set the NAS to sleep the drive when idle.

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