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