Best Free Disk De-fragmenter


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Fragmentation: why it happens

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.

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.

So when testing defragmenter software we are going to evaluate it with some 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.

Well, it's time for action now and let me introduce you to the de-fragmenters.


UltraDefragUltraDefrag is simple yet has a lot of customizable options through text files and scripts via two mouse-clicks. Not only is the defragmentation super fast, but also you are not going to notice it's working! You can keep doing your things while UltraDefrag does what was born to do… defrag. It performs so well you are going to want to carry it in your wallet. A lot of varied boot defrag commands. If your goal is to optimize your system startup at maximum, this is what you need.


MyDefragMyDefrag, JK defrag with a GUI (Graphical User Interface). Bad? No, just awesome!

Unbelievable power user options for everyone without having to configure any script. Just select the option that best suits your needs and it's done. MyDefrag employs an algorithm that places the most used files at the beginning of the disk. This decreases access times because the actuator arm of the hard drive has no need to move to the end of a disk to search a file.

If you don't know what a HDD looks like, please see below:

The trick revealed and a little science.

When you turn off your computer (or Windows shut downs your HDD), the actuator arm has a designated "landing zone" (a specific sector at the beginning of the disk) that remains stationary until the next startup. This is to avoid disk scratch and therefore, data loss (data is read via magnetism, touching surfaces is not required). When turned back on, the closest sector to the actuator arm is already near the "landing zone" (beginning of the disk) so it's faster to read files on that sector than others in outer zones of the disk.

Also, the surface distance travelled is considerably less in the inner sectors of the disk. So, placing files at the beginning of the disk is the best idea.

MyDefrag is not the only defragmenter capable of doing this, as many others include an option. However, MyDefrag achieves this in a much simpler way. This is combined with a good “fast defrag”; the choice of specific options, many others by scripting, and excellent defragmentation methods and simple scheduler options.


This little boy, DiskTune, is not exactly a kid. Despite the use of Windows API to do defragmentation jobs, it's incredibly fast, simple and lightweight. Many useful options just a couple pixels of distance. Direct access to usual options such as Analyze, Defrag (quick), Optimize (rearrange) and Compact (defrag free space). The best thing about DiskTune? The ability to create a shortcut to your desktop and then double-clicking it to run a fully customized defrag. Four words—“one size fits all”.


Defraggler thumbnailPiriform's Defraggler—The first thing that caught my attention when first opening Defraggler was a green word, GOOD. I quickly realized it was telling me about S.M.A.R.T. Status (information provided by the disk itself, reporting temperature etc). This is a great feature and has its own tab on the program for detailed view.

In terms of defragmentation ability, Defraggler is one of the best choices you could make. It performs a very fast “quick defragmentation” with decent file reorganization but if you perform a complete defrag process, which takes longer, you obtain results that are worthwhile. Your files will be together as they should be as solid as a concrete wall. Defraggler also supports scheduling, low priority and boot defrag. Highly recommended.


MyDefragmenterMyDefragmenter, Ultradefrag with a very simple, intuitive GUI plus a full scheduler which has the ability to program defrag while shutting down or starting up computer. Includes a 24/7 support by phone call and online help.


Auslogics Disk Defrag thumbnailAuslogics Disk Defrag is another quality disk defragmentation program. During a fresh installation the installer asked if I wanted to install a Tool Bar and/or change my home page. These were easily de-selected before the installation process began. Auslogics Disk Defrag can be ran from a easy to understand GUI (Graphical User Interface) or you can use the command line tool for more advanced users. Auslogics also optimizes defragmented files and space by defragmenting free space and moving system files to the fastest part of the disk. The software is designed to defrag multi-terabyte volumes. If you choose you can defragment a particular folder or a single file by selecting the file out of a list of fragmented files. The program is set-up for automated defragmentation and will allow you to analyze your disks before you defragment. Auslogics also has a portable version available which can be run directly from your USB drive. Both versions are free and are allow for home or commercial use. The developers also have several articles regarding defragmenting your hard drive including How to defrag your drives the right way: 7 defrag tricks to learn today". This article includes topics such as temporary files and how to prevent the loss of your system restore points. The software only supports 64 bit on Windows 7/8 operating systems. The developers have updated this software twenty-four times in the last thirty four months, eleven of those were in 2012. Needless to say continued development of the product remains strong.  I have used this program on all of my computers for the last couple of years without any issues. Operating systems I have successfully operated on include XP 32bit; Windows 7 32 & 64bit.


Also reviewed but not included:

-Puran Defragmenter

-O&O defrag free edition



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

Quick Selection Guide


Gizmo's Freeware award as the best product in its class!

Runs as a stand-alone program on a user's computer
System files defragmentation. Incredibly fast in all tasks. Power (scripting) features.
Some settings only accessible by configuration file (txt).
681.6 KB
32 and 64 bit versions available
Open source freeware
A portable version of this product is available from the developer.


Runs as a stand-alone program on a user's computer
For average and power users
Not regularly updated
2.035 MB
32 and 64 bit versions available
Unrestricted freeware
There is no portable version of this product available.


Runs as a stand-alone program on a user's computer
Very Fast. Can create shortcut to double click customized defrag.
Windows API. Needs to improve system resources usage
1.06 MB
32 and 64 bit versions available
Unrestricted freeware
There is no portable version of this product available.


Runs as a stand-alone program on a user's computer
Very solid piece of software. Updated regularly. Now with S.M.A.R.T. monitoring.
No optimization feature yet.
3.6 MB
32 and 64 bit versions available
Free for private use only
A portable version of this product is available from the developer.

Auslogics Disk Defrag

Runs as a stand-alone program on a user's computer
Very fast at analyzing and performing a quick defragmentation.
Optimize function could be faster.
5 MB
32 bit but 64 bit compatible
Unrestricted freeware
A portable version of this product is available from the developer.


Runs as a stand-alone program on a user's computer
Well recognized Ultradefrag engine. Excellent scheduler.
Not regularly updated.
1.8 MB
32 bit but 64 bit compatible
Feature limited freeware
There is no portable version of this product available.
Running on x64 computer requires download and replace DLLs available at Mydefragmenter website

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

defrag disk, defragment hard disk, disk defragmenter, free disk defrag software.

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Average: 4.1 (227 votes)


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

With mitch permission, I'll recommend you to make a disk check:

-Command prompt

chkdsk /f /r /b (could take a while)

I suspect a corrupted mft

Are you recommending that I schedule Check Disk?

If so, I just ran it after I uninstalled Auslogics and installed Defraggler.

What is a corrupted mft?

What is mitch permission?

I'm sorry, but I simply don't understand the jargon.

It is not logical that, eventhough Auslogics' optimize and defrag times have increased, that Defraggler takes greater than a day to defrag.

If that's normal, than I'll look elsewhere.

Sorry about poor explanation

A corrupted Master File Table could lead to slow information retrieve from disk so is slows down average read. Defrag use MFT to organize files.

You have two different defragmenters with different algorithm, so is normal it display different estimated time.

Yes. I recommend you to open an elevated command prompt and run a check disk

If you need more help how to do this, please ask.

rmitch is the former editor of this section, and I'm the older editor so, with his permission I'll take your question

You provided an excellent and speedy response. You don't need my permission to come and play on the playground you built. I tried a number of products when I started as the editor. For the dozen and a half I tried, I couldn't find anything better than what you had already quantified. I'm sorry that MyDefrag is retiring support and advancement of their product, but it still does a great job. Thanks again for the sound advice. I think others will find the information useful as well. I usually check in for questions every other day, but my job includes Disaster Recovery. I had an incident that kept me busy 18 hours a day for four days. Still tired from that. I wanted to give you my personal Thank You! for the foundation you built, and for providing prompt and valid advice to a reader in need. Take care! -rmich45

Thanks for the help...

Chkdsk ran all night, didn't find anything.

Everything is OK, which I knew it would be.

I had just run chkdsk a week or so ago when I uninstalled Auslogics - there was nothing then, nothing now.

Not sure where to next...I am still baffled why Defraggler was taking so long in either mode, quick or full on defrag.

mitch is the editor of this category... rmitch45. MFT is Master File Table: He did not ask you to schedule a check disk. He gave you the command to run from command prompt in order to run check disk immediately. Command prompt can be started from Start Menu --> Run --> Type "cmd" and press Enter. This will open the command prompt, where you can enter the command that he told in his post.

Thanks Anup.
D@mn, guy, you still as fast as a thunder