Back to Basics – Disable Data DeDuplication

Here is a quick guide on how to disable Data Deduplication. In this example I disabled Data Deduplication for my F: volume.

1. Make sure no applications or services are writing data to the volume.

2. Check the actual size of your content, and make sure you have the space available on the disk (with room to spare)

3. Unoptimize the data by running the below PowerShell command and wait until it finishes.

Start-DedupJob -Type Unoptimization -Volume F: -Full -Wait


  • The Unoptimization command above, when finished, will also disable data deduplication on the volume to prevent further data deduplication on the volume. You can verify this via the Get-DeDupeVolume cmdlet.
  • The Disable-DedupVolume cmdlet should only be used when you want to keep content with data deduplication but prevent more content from being deduplicated.
  • Unoptimizing a volume can take a good while, and also, the -Wait parameter is quite useful, because otherwise you need to monitor the dedup job process via the Get-DedupJob cmdlet to know when it's done.


Unoptimizing a volume can take so much time, it's sometimes quicker to copy the deduplicated data to a volume on another disk, format the volume on the first disk, and copy the data back.

As an example, unoptimizing only 40 GB of content can take 10 minutes.

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Johan Arwidmark

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