Deduplicated volume wont free up or release disk space? A lesson in Server 2012

Recently I ran into an issue where my Data Dedupe on Windows Server 2012 was not releasing space back to the OS. I would delete files over and over. Attempt disk cleanup but still nothing would happen. This only seemed to affect the volumes I have deduplicated then it hit me.

Garbage Collection; this feature will scan the disks and look for any files or free blocks that are no longer used and remove them. However this was set to run once a month or something  ridiculous  like that. For me that is not an option.

Problem: I am unable to free up or release disk space back to the OS after deleting files on a deduplicated disk in Windows Server 2012. This guide will also apply to dedupe on Windows 8, see my previous post.

Solution: Enable garbage collection right away to free up disk space; then schedule it if needed. 

First thing we need to do is open Power Shell. Once it is is open be sure you know the disk letter that you want to clean up. Ill use H: as my example. Type in the following command:

Start-DedupJob H: -Type GarbageCollection -Verbose

You will get output like below:
5-22-2013 8-11-03 AM

Now you will want to verify how far it is so simply type in:


You should see the job like I did here:
5-22-2013 8-13-15 AM

2 thoughts on “Deduplicated volume wont free up or release disk space? A lesson in Server 2012”

  1. I am having a very similar issue with this, i tried disabling the dedeplication then re-enabling and i get a “the data dedeuplication service detected an internal folder in not secure.” error is powershell when i try to run the garbagecollection script. I am about to migrate to this server as a new file server and its very concerning that i have ended up with a drive i cannot seem to use or recover from. If this was in production i would be very stressed. Im sure the reason it first started was because when i was copying data to the dedupe drive it ran out of space(oops). Has anyone else had this issue/recovered from this type of error. My next stop is a microsoft tech support call….

    1. Yeah if you have MS support then I would call them but that depends on your MSDN Subscription. You might be able to get help from them as for that error I cant say I have seen that before. Let me know if you find a solution.

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