# Backing up WD MyCloud PR4100 NAS to move to Synology NAS

**URL:** <https://forums.spacerex.co/t/backing-up-wd-mycloud-pr4100-nas-to-move-to-synology-nas/3497>\
**Category:** Synology\
**Tags:** help, backup\
**Created:** [November 1, 2025, 10:45pm UTC](https://forums.spacerex.co/t/backing-up-wd-mycloud-pr4100-nas-to-move-to-synology-nas/3497 "2025-11-01T22:45:01Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![rpcb61](https://forums.spacerex.co/letter_avatar_proxy/v4/letter/r/5f8ce5/32.png) [@rpcb61](https://forums.spacerex.co/u/rpcb61)\
**Post date:** [November 1, 2025, 10:45pm UTC](https://forums.spacerex.co/t/backing-up-wd-mycloud-pr4100-nas-to-move-to-synology-nas/3497/1 "2025-11-01T22:45:01Z")

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I have tried to backup my WD MyClouid PR4100 NAS with USB backup. All folders backup succesfully apart from the critical “Backups” folder share that I have to a USB 2 drive.

I have tried multiple external USB Hard drives, but all fail on this folder but back the other folders up OK.

I have about 10TB that I need to backup for this folder and have at 20TB drive.

Given it keeps failing and doesn’’t tell me why, when it fails I can no longer see other data backup up data either once I run the backup and it fails looking at the quickest way to back this up.

I have a copy of all other data on another drive Ok that i can read as long as I don’t try to backuo the Backups share on it.

Total space of all folders / shares is 12.5TB - so I have plenty of space on the 20TB Drive.

I am limited by the 1Gbit LAN port on the WD NAS so will take awhile. (like multile days using a laptop / PC to manually copy files to the USB drive attached to this.

Is there a way to find out why the USB backup is failing? if not - what is quickest methord to urgently back this backups shafe up successfully?

PS: I don’t have another WD NAS to backup to.

I haven’t yet purchsed my new Synology NAS which wilm replace this (I am waiting for Black Friday offers)

I could wait until i have this and then use acrtive backupo but don’t want to risk this incase my device fails in the meantime!

Any help and advice will be kindly appreciated.

Rich

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<div class="post-metadata">

**Author:** ![rpcb61](https://forums.spacerex.co/letter_avatar_proxy/v4/letter/r/5f8ce5/32.png) [@rpcb61](https://forums.spacerex.co/u/rpcb61)\
**Post date:** [November 3, 2025, 12:09pm UTC](https://forums.spacerex.co/t/backing-up-wd-mycloud-pr4100-nas-to-move-to-synology-nas/3497/2 "2025-11-03T12:09:31Z")

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Just to confirm I tried yet another external USB drive to backup just the backups folder and this has backed up successfully.