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Windows 7: Defragmenting 2TB external HDD, lost ~400GB since it started

11 Sep 2014   #1

Windows 7 Professional SP1 x64
Defragmenting 2TB external HDD, lost ~400GB since it started


Although the process hasn't finished yet, Defraggler is reporting that around 400GB has been taken up since it started!?! Why has it taken up 400GB!?! Surely something must be wrong?! At the time of writing, the defrag is still going (it said about 500GB was fragmented at the start) but its saying there almost a day left on it.

Can somebody explain this please?


My System SpecsSystem Spec
11 Sep 2014   #2

Microsoft Community Contributor Award Recipient

Windows 7 Home Premium SP1, 64-bit

What does "taken up" mean in this context?

What makes you think anything is wrong?

Let it finish.
My System SpecsSystem Spec
12 Sep 2014   #3

Windows 7 Professional SP1 x64

Before I started defrgmenting my hard drive, I have 1.0TB used and 800GB free, but now the drive has 1.3TB used and 500GB free.
What has taken up another 500GB?
I get that Defraggler and similar programs move files around on the plater to reduce read times, and to do so *some* drive space may be lost during the process, but to lose 500GB seems extreme, so I was wondering if that was ok, or whether the program has gone rogue
Before I started defragmenting, about 28 hours ago from when I'm writing this, it said there was 500GB of files and at the last check it was 56% finished.

So as I said, it seemed strange that 1/4 of the drive has been used up since it started, as I wanted somebody to tell me if something was wrong, as I have never known that much storage to be used during a defrag.

My System SpecsSystem Spec

14 Sep 2014   #4

Windows 7 Professional x64

Same thing happened to me an hour ago, i decided to defrag my 160Gb C: drive and when the defrag process was finished i had 0 bytes free space left on the drive. I was using the Win7 defrag tool. I did notice that during the course of the defrag process every time it defraged for example Pass/1 step, after that was done I'd lose like 10Gb.Bottom line is now all my free space is gone and i cant retrive it.

// I tried chkdsk /f - NO LUCK
// Defraged C: again - NO LUCK
// Disk Cleanup , well this here was interesting, i gained some space from this about 2Gb and after 10Miunutes or so all my space was gone again

Anyone with a solution please help!
My System SpecsSystem Spec
14 Sep 2014   #5

Windows 7 Professional x64

I found a solution here: How to Delete Shadow Copies from your Hard Disk Drive to Free Up Space - Configuration - Windows 7

1. Download WinDirstat
- This program will show you what exactly is consuming how much space in your drive, in my case i had a log file consuming 148Gb duno how that came about.
- The program will also show you the amount of space occupied by shadow copies (in black)
-if the space is too much you can then clear it as follows using the following commands:

// Open elevated cmd

1. type vssadmin list shadows
2. type wmic
3. type shadowcopy delete
4. When prompted "type y, hit enter"

see How to Delete Shadow Copies from your Hard Disk Drive to Free Up Space - Configuration - Windows 7 for detailed
explanation on what this is or does,

Hope this helps
My System SpecsSystem Spec

 Defragmenting 2TB external HDD, lost ~400GB since it started

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