Best Free Disk De-fragmenter

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When testing defragmenter software, we evaluate it with these parameters:

  • Speed of analysis on fragmented files: Isn't it speed we want from our computer?
  • Speed of defrag;
  • Some extras: such as scheduled defrag, shutdown PC when done, etc.;
  • Defrag capabilities: Why is this placed in last position? Because almost all of today’s defragmenters can perform this task with very similar results.

With these parameters in mind, we found a few we could recommend with the best of these as good as any commercial product.

Read also Fragmentation: Why does it happen? and Defragmentation: Do you need it? at the end of this page.


Rated Products


A simple and super fast defragmenter

Our Rating: 
License: Free (Open source)
System files defragmentation. Incredibly fast in all tasks. Power (scripting) features.
Some settings only accessible by configuration file (txt).
Read full review...


Unbelievable power user options for everyone without having to configure any script

Our Rating: 
License: Free
For average and power users.
Not regularly updated.
Read full review...


Perform quick defragmentation with decent file reorganization

Our Rating: 
License: Free (Private/Educational use)
Very solid piece of software. Updated regularly. Now with S.M.A.R.T. monitoring.
No optimization feature yet.
Read full review...

My Defragmenter  

A simple and intuitive defragmenter plus a full scheduler

Our Rating: 
License: Free
Well recognized Ultradefrag engine. Excellent scheduler.
Not regularly updated.
Read full review...

Also reviewed but not included:

  • Puran Defragmenter
  • O&O defrag free edition
  • Others

Feel free to suggest any software not already mentioned for review.


Related Products and Links

You might want to check out these articles too:


Fragmentation: Why does it happen?

Suppose you are browsing the web, downloading your favorite songs and installing an application all at the same time, how does your system write all these files without any interruption to your activity? Well it's simple: it responds to all applications' write requests (I/O operations) by writing all files at a continuous location on your disk.

Representation of a disk track:

(Fig. 1)

Yellow: Temporary written internet files
Red: Installation (Game)
Blue: Song cache

The purpose of disk defragmenters is to reorganize such files which are supposed to be together. An ideal situation after defragmentation would look like this:

(Fig. 2)

But what happens when you uninstall, delete, or simply clean your temporary files? Imagine yourself uninstalling the application (game) you installed. The disk could look like this:

(Fig. 3)

The white zone is empty space without fragmentation. A disk looking like this will have just a little or even imperceptible impact on performance. In this case defragmentation is needed but not critical.

The last thing you want to see is a hybrid combination. Files very fragmented fig 1 and empty disk space fig3 but instead of contiguous clean sectors you'll find what we call fragmented empty space. And this is what it looks like:

(Fig. 4)

This is the worst case scenario. Overall system performance will be compromised and fragmentation is critical. You should defragment (defrag) or let your defragmenter schedule and execute the defrag process for you.


Defragmentation: Do you need it?

Standard mechanical HDDs (hard disk drives) will benefit from defragmentation and continuous disk use, because when spinning, it keeps remagnetizing the HDD plates. But if you own an SSD (solid state drive) you SHOULD NOT defrag or install any defragmenter application because it will shorten the life of the drive.



This software review is copy-edited by Ian Richards. Please help edit and improve this article by clicking here.

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Your rating: None
Average: 4 (239 votes)


I have used UltraDefrag for a couple of weeks. Defragmentation is quick, but optimization generally takes about 24 hours :( I run Windows 7.

Missed defrags here: Auslogics defrag, IoBit defrag.

Since migrating to Windows 10, I've spent a fair amount of time analyzing this topic, and finally have uninstalled
all my 3rd party De-fragmenter software and reverted back to using the default Microsoft one.
Simply put - In my opinion Its no longer worth the effort as the built-in Microsoft utility is doing a pretty decent
job these days. (Even for a faster boot up).
Gone are the days when this issue required a 3rd party solution....that's my 2 cents!

I was surprised not to've seen any mention of the amazing Windows defragger, "Vopt". I've been using it seemingly forever, and thought I'd bring some bittersweet news.

Howard Barry Emerson, author of Vopt and co-founder of Golden Bow Systems, passed away nearly a year ago. As is headlined on the company's website, serials for both versions of Vopt are being offered at no charge. "In accordance with Barry's wish", reads a statement at, "Vopt is his bequest to Windows PC users."

Those who've been long-time Vopt users — especially those who've enjoyed personal contact with Barry over the years — feel the loss of his good heart and superlative programming skills.

Thanks for everything, Barry. We miss you....

I just ran UltraDefrag 7.0.1 through Virus Total and here are the results. Out of 56 scan engines, 8 detected malware.
AVware Trojan.Win32.Generic!BT 20160401
AegisLab Troj.Gen!c 20160401
Cyren W32/NewMalware-LSU-based!Maximu 20160401
F-Prot W32/NewMalware-LSU-based!Maximu 20160401
McAfee-GW-Edition 20160331
Rising PE:Malware.XPACK/RDM!5.1 [F] 20160401
Symantec Trojan.Gen.2 20160331
VIPRE Trojan.Win32.Generic!BT 20160401
I suspect they are false positives, but the defragger programs should be checked against VT or other multi-malware scanners before making any recommendations.

I had to answer this.
There is no need of third party defragger if you are using Windows 7, 8, 8.1, 10.
I use the 10 and would not mess with any of these third parties anymore. Lets move on. Rule of thumb when using a Windows system: Do not risk its stability by installing lots or some unnecessary third parties or messing with its internals too much. Just run it as vanilla as you can and it will thank you.

When obtained via the link on our page, the x64 bit version gets 3 hits.
The x32 bit version does have more but these (as with the x64 bit) are all false positives as already documented on the developer's Sourceforge page. MC - Site Manager.

Is the MyDefragGui found on the same as the MyDefrag mentioned on here, but with different user interface?

You say Defraggler is unrestricted freeware. In fact, while Defraggler Free is unrestricted in terms of its features, it is licensed for non-commercial use only. It is something that e.g. SOHO users like me need to know. In fact, I, too, missed that point at first, and installed it (long before reading your article) on a netbook I use for my professional activities. After some time, I realized I was violating the license, and removed it.

Thank you for pointing this out. The product details have now been updated. MC - Site Manager.

Sadly, the MyDefrag website has closed as of October 1, 2015. The last version, 4.3.1, is still available at many reputable websites, such as:
It's still the best free defragmenter out there, and works with all versions of Windows from XP to 10, including the corresponding Server versions. The comparative review mentioned by AJNorth is excellent.

Guess all good things come to an end, been happily using MD for years and will continue to do so, always got immediate responses from Jeroen over at his Forum which I see is also gone.
Happy trails JCK, that's one neat piece of software you've left us.

I use JkDefrag portable from Portableapps and it's pretty easy and straight forward.
Why is it only mentioned in MyDefrag's review?
Why would it need a gui, it already has one?

Re: "Why is it only mentioned in MyDefrag's review?"
Because the programmer changed the name from JkDefrag to MyDefrag when updating it a few years ago.

An interesting comparison of the various defragmenters available (both free and boughten) is The Big Windows 7 Defragmenter Test, by Christian Hofmann (updated 2014.05.21) -- .

(I should be especially interested in the opinions of the above article from 'Gizmo' Richards and MidnightCowboy.)

Happy -- and safe -- holidays to all!



And here's another test with different results The main factor I see in both of them, is the software that's used to test the 'Before' and 'After' states. In your tests, it was MyDefrag that was taken, and it became 1st, whereas in the tests given in my link, Defraggler was taken which came 3rd, while MyDefrag came 6th. Honestly it's hard and not a logical choice to simply follow one test.
Hi AJ, I always tend to smile a little when I see stuff like this although I appreciate that for the technically minded such reviews are of interest. I think the crucial statement is in his summary. "The results turn out pretty disappointing. Only MyDefrag 4 improved the performance by 13%, which is in the range of where an improvement is even noticeable. O&O Defrag Pro 16 just managed to get to 8%. But the results should be considered relative: Only the boot time and the start time of Civilization could be noticeably improved, there was no noticeable improvement for other applications, though". I also apply the same criteria to programs like memory optimizers, tweak tools and registry cleaners. Maybe I'm even more strange than most folks already believe, but in my lifetime I have never seen a computer "speeded up" by anything that wasn't more likely to make it potentially unbootable during the process. Again quoting from the review. "The SSD is constantly on the 1st place, indicating that a piece of hardware can bring more performance than software ever could". The same applies to the proven advantages of increasing memory capacity instead of trying to tweak or clean your way to some mythical speed improvement via a software application. 95% of my time is spent using Linux so no defrag is needed. Two of my desktops and the laptop are dual booted with Windows however but I keep all of my heavy stuff including exe's, image and video files on an external drive. I defrag this about every couple of months using MyDefrag just to keep it tidy but I've never had any issues with speed or file access unless such was caused by a security related software program. MC Site Manager.

I don't know if the author of this article don't think that shadow copies are important but most of the above don't take care of those. I think Auslogics is the only one, but I saw that O&O got better points on other sites so that is the one I use nowadays.

A concern over Auslogics which I've been using for years. Just installed on a reformatted laptop. I watch closely for toolbar check marks. Not sure if they've gotten sneaker about their location but I sure didn't see one.

It installed a redirect home page to bitable. I tried everything possible to change it back to Google. The only thing that worked to remove it was HiJackThis.

Here's how they did it:
If you Right click on browser's shortcut and choose 'Properties', the section for 'Target' says: "C:\Program Files\Mozilla Firefox\firefoxexe"
To the end of that line, Auslogics adds "", so now that whole line reads like this:
"C:\Program Files\Mozilla Firefox\firefoxexe" ""

really need this to try to correct my computer

MyDefrag doesn't defragment completely ("Monthly" script) and works VERY slowly. After 10 hours of defragmentig MyDefrag finishes (with many not defragmented files, this files aren't locked), then I run it again, then if runs 10 hours and result is the same. I have 1 TB not so much fragmented disk (and 25% free). I can't understand why is defragmenting so slow. If I would only copy the data to another disk, then I would have drefragmented disk in 5 hours :-|
And when you have MyDefrag screen saver and you want run MyDefrag manually, thne you have switch off its screen saver :-(

You should really consider again IObit's SmartDefrag, current version (3.1) has a lot of improvements vs previous version, it even has a new defrag engine and new algorithms to defrag, optimize and prioritize files!

I used to have PerfectDisk 13, but after installing and testing SD 3.1 I'm really impressed! My computer boots faster and is more responsive than when I had PerfectDisk 13.

The boot defrag works way better than other free and commercial software, and it's not obtrusive like PerfectDisk popup window and autorestart.

Indeed SD 3.1 should be the #1 defrag and optimizer for HDD among free and paid.

I'm a really satisfied user!

I would like to see a review of WinContig.

Any thoughts on Iobit's SmartDefrag? It has been around for years and has boot defrag options. Please consider for review.

This review currently has no editor so no new programs will be considered for inclusion until someone volunteers to take it over. MC - Site manager.

I have a question about Defraggler...

I have been using Auslogics Disk Defrag for a number of years, but recently uninstalled it because the length of time to run "defrag and optimize" is now over 1.5 hours, when it could be accomplished in 20 minutes or less for years.

So, I tried Defraggler.

I must be incredibly stupid because I simply can't understand why Defraggler keeps telling me that it is going to take ">1 Day" to defrag.

Even quick defrag tell me that it's going to be 5 hours.

What am I doing wrong?

This morning after running the analysis again, there were 319 fragmented files, 603 MB, out of a 250 gig HD, with 65% free space.

I have yet to complete a defrag because this is completely illogical, it simply makes no intuitive sense, when I keep reading in various forums, including the Gizmo's forum, that it is so quick.

Can anyone please explain this before I uninstall this program?

I have been using 3rd. party defrags for a few years, but I am very flummoxed by recent behavior - I can't understand why all of a sudden these programs are now taking so long to get the job done.

Nothing, and I mean nothing has changed on my system from one update to another, no new software, not in a long time.

I would suggest you a very simple solution, mate: Just stop bother with all these free defrags. From time to time run "Analyze" button of built-in Windows defrag utility and if it tells you: "Your file system performance is good, you don't need to defragment at this time" (or something like that) - just go and enjoy your computing and stop worrying about nothingness...

Sometimes the "fragmentation/defragmentation" issues is too much overrated - let's not make them more significant than actually they are...

It sounds like you received some great advice that worked for you! This is an excellent community of users willing to help each other out. Reading the back and forth on this issue re-enforces my beliefs about the online freeware and open source community. You all are the best! As far as sheer speed goes, UltraDefrag is very fast. Defraggler has continuous updates, product enhancements, and notifies you when your version is out of date. I've written scripts to run it at boot and defrag paging files. There are positives to each of them. Last week, I uninstalled Auslogics from my personal laptop. My computer was slowing down, and I investigated. A simple Task Manager session on running processes sorted by memory use told me Auslogics was chewing up the largest portion of my memory. I can't say it would do that to anyone else, but that was my personal experience. An issue has to be consistent, predictable, and repeatable before I would say there is a flaw. Thanks to everyone! rmitch45