Causes & Fixes - WD MyCloud PR4100 shows full

If your WD MyCloud PR4100 is showing full capacity on a 2x4TB drive setup, even though you’ve only stored 2.1TB of data, you’re not alone. Many users report seeing incorrect storage usage or alerts that the device is nearly full, despite having ample free space. This issue can be confusing and concerning, especially when you're relying on the device for backups, media, or work files.

In this article, we’ll explore why your WD MyCloud PR4100 shows full, common causes behind the misreported storage, and what you can do to fix it or prevent it from happening in the future.

Understanding the Drive Configuration (2x4TB)

Your WD MyCloud PR4100 with two 4TB drives can be configured in several ways:

JBOD (Just a Bunch of Disks): Each drive operates independently, giving you a total of 8TB.

RAID 0: Combines both drives for performance and capacity (8TB total, no redundancy).

RAID 1: Mirrors data from one drive to the other (only 4TB usable).

Spanning: Combines drives sequentially, like JBOD but behaves like a single volume.

If you’re seeing your system as “full” or nearly full when there’s only 2.1TB of data stored, your configuration and file system might be to blame.

Possible Causes of the “Drive Full” Issue

1. RAID Configuration (RAID 1 = Only 4TB Usable)

If your drives are set up in RAID 1, only one of the 4TB drives is actually used for storage; the second is a mirror. That means your 2.1TB of data is over 50% of usable space, which could prompt a nearly full warning.

✅ Check in Dashboard: Go to the WD MyCloud web interface and confirm your RAID setup under Storage > RAID.

2. Snapshot Backups or System Cache Taking Up Space

The PR4100 supports snapshot backups and Time Machine backups, both of which can consume large amounts of hidden space.

✅ Fix:

Navigate to Backups > Snapshot and delete old or unnecessary snapshots.

Check Time Machine or other automatic backup configurations.

3. Recycle Bin or Hidden Share Space

Deleted files can still reside in the device’s Recycle Bin or hidden shares, especially if the Recycle Bin feature is enabled.

✅ Fix:

Go to Shares > Recycle Bin in the dashboard.

Empty the bin manually to reclaim space.

4. Misreported Storage Due to Indexing or File System Errors

Corrupted file indexes or system errors can cause your NAS to misreport disk usage.

✅ Fix:

SSH into your device (if you’re comfortable) and run file system checks.

Alternatively, reboot the device and allow it to rebuild the index.

5. RAID Degradation or Sync Issues

If a drive has failed or RAID is rebuilding, the system may report used space inaccurately.

✅ Fix:

Check the RAID status in the dashboard under Storage > RAID.

If a rebuild is in progress, wait until it's complete to reassess available space.

How to Reclaim Space and Avoid Future Issues

🔄 Regularly Monitor Storage

Use the dashboard to keep tabs on storage usage, snapshots, and logs.

🗑️ Empty Recycle Bin

Enable auto-empty for the Recycle Bin to prevent hidden buildup.

🧹 Clean Up Backups

Review Time Machine and third-party backups to avoid duplicate or bloated copies.

📤 Move or Archive Large Files

Offload old media or non-critical files to an external drive or cloud to keep your NAS light and efficient.

🔧 Run Firmware Updates

Keep your MyCloud firmware up to date to benefit from storage reporting fixes and performance enhancements.

Final Thoughts

When your WD MyCloud PR4100 shows full despite having only a fraction of the capacity used, it’s usually related to RAID settings, backup processes, or hidden files consuming space. By understanding your drive configuration and regularly maintaining your system, you can prevent false full-drive alerts and keep your NAS running smoothly.