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.

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


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.

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)


Were you using a Beta version? Can you isolate the issue to a particular setting or specific action. I am only asking because the product has consistently been highly ranked, and after testing on my personal machines, the licensing permits use within government and business environments. I have substituted UltraDefrag on many Windows 7 machines within my workplace due to the faster defragmentation times as well as the optimmization. I have it on about 30 desktops now in place of Defraggler. It has been performing very well on the Dell Optiplex Systems I am using it on. Thanks for your feedback. A word of caution to all: The open source and free tools are offered as is. The Open Source products generally have an active group of followers that are ready, willing, and able to assist with any issues and bugs. In many cases, I find the forums for these products to have better support than paid software. You may want to pose your specific situation in a forum. SourceForge can probably link you to the community. Keep me posted.

Nope, I was using the newest stable version. I started the full slower optimization and left the house. Came back later to a shutdown PC. Started it up and got the message that Windows couldn't start. Two options... repair or start Windows normally. Starting Windows normally would just put me in the same spot. When I tried a repair, Windows gave me a message that it couldn't do it. Can't remember exactly what the message was. Luckily, I keep most of my stuff on an external drive! I would love to have been able to look at the events if Windows was able to log them. I still have the drive if you know where I could look for the events.

I also like the many options that this software gives you but I'm scared! Going back to Defraggler for now.

That is definitely unfortunate. The technician in me would love to look at the Event logs and the dump file. I am the editor of the defragmentation page on a voluntary basis as a way to contribute some of my experience and to answer questions related to this topic. Consequently, I have to be cautious about what I write and how I write it. I do not advocate that anyone opens or browses through Windows system files without the explicit warning that doing so can trash the Operating System. However, I can tell you that the log files are located within the Windows system files. More specifically, the .evt files are located within the %SystemRoot%\System32\Config folder. The files can be imported into a Comma Separated Values format (.csv)that is very similar to Excel. If you decide to have an IT Pro retrieve them for you, the answer to the crash will probably be in both the Application and System logs. As to Defraggler, it has always been stable, frequently updated, and on my personal top three list of de-fragmentation tools. I have installed Defraggler and it's sister program CCleaner on more machines than I can count. Defraggler will do a great job for you, is highly customizable, can be set to replace the Windows De-Fragmentation tool, and run automatically through a scheduled task. You can't go wrong with all of that. In my testing, if I find a negative impact on Windows from any of the products, I will certainly share that as part of creating an objective and unbiased list. Thanks again for sharing the information with me and the other readers!

Why not to review and include Ultimate Defrag Freeware Public Domain Edition?

It's old, released 2008, and non-supported version of the main commercial one, but still rather good and advanced defragger alternative, and in my opinion should be mentioned here. Is it for the same reason that the O&O freeware is not reviewed? Both are more adware than freeware :)

"More than just a defragger, UltimateDefrag is also a hard drive file placement optimizer that enables you to defrag and place your files in the areas on your hard drive where you achieve maximum performance. 80% of the time you only use 20% of the files on your hard drive. UltimateDefrag places your rarely used files out of the way and onto the slower performing areas of your hard drive making your drive perform like a new, almost-empty drive. Version 1.72 includes unspecified updates."

Read more: UltimateDefrag Freeware Edition - CNET

Moderators comment: Be sure to only use the "Direct Download Link" button to avoid the cnet wrapped installer and it's unwanted components.

It is definitely something I can look at. I am hesitent to download installations from CNET because of the instalation wrappers that attempt to redirect home pages and add superfluous toolbars, etc. I will look for an alternate download site. Thanks for sharing your thoughts. Do you have an idea of why it has not been updated more recently than 2008? Two of the products I am testing have already been updated within the last month. Active updates indicate that a product is heavily used and the developers have an interest in meeting the needs of the customer base. Thanks again for sharing!
I have just recently joined as an editor of this topic and Ultimate Defraf-Freeware-Edition is on a list of products to test. Many free products are as supported. It costs money, either through donations, ads, or other avenues of revenue to support the availability of freeware products. I do want to emphasize the moderator's comment that with CNET Downloads, the software is bundled inside a wrapper. If you choose the default installation or don't take care to uncheck and decline additional offers, you will ens up with more than the software. I appreciate your conviction for UltimateDefrag. Thank you!

I don't use it myself, I prefer other one, but it is in my opinion a good disk defragmenter to be mentioned and reviewed on a freeware disk defragmenter list as an alternative to these that are already mentioned.

Yeah the CNET is crap nowadays. Hard to find a download link for it and that was the first one. It seems that Disktrix isn't offering it anymore, although they seem to still host it.

Here is a better alternative link:

And Direct Download link from Disktrix:
[Edited out, direct download link is not allowed.]

I appreciate the suggestion. I will definitely check it out. To all of you, I will run my comments through a spell and grammar check before I post again. Thanks for overlooking the handful of typos! I'm a networking guy by trade, and writing anything other than Standard Operating Procedures, Network maps, and sub-netting is new to me. I did get my career start on the desktop and software end of IT though. I got into trying, using personally, and implementing in a business environment, good open source and freeware programs that help to keep computers running optimally. Disk De-fragmentation is one of those areas that can create a genuinely visible improvement in the speed and performance of a computer. Thank you again!

Hello rmitch,

hope you have a good time with this.

One thing about defragging I've rarely seen mentioned is that many programs perform badly if hiberfile.sys and pagefile.sys get in the way. Temporarily disabling these, even on a disc with lots of room on it, can magically allow the program to do its job. I'm not sure if I'd advise the inexperienced to do this though.

One bonus with temporarily disabling the pagefile is that it gets defragged properly, something that a lot of programs don't actually seem to manage.

Thank you! One of the criteria I am considering is the native ability of a product to scan these files that Windows locks when the Operating System is running. Many of the alternatives include an option now to scan and defrag the paging file and hiberfile.sys. For those unfamiliar with the concept, the pagefile.sys is a portion of the hard disk that Windows uses as a supplement to RAM (memory). Windows will use the system RAM for the high priority tasks and services running and the paging area for inactive or queued functions until it needs them and they are moved to RAM. In Unix and Linux, the equivalent is the swap file. Feel free to Google this. I try hard to explain concepts in plain English, but some of the specifics become lost in translation. Thanks for the very valid, and very excellent reference to the hiberfile.sys and pagefile.sys.

I may have missed it, but I don't see a compare with the windows built in defrag utility. Is there a significant gain in using one of these freebies.

I feel as if I only answered part of your question. It is extemely difficult to create a benchmark for a defragmentation product. Once you have run one on a system, improvements have already been made that will affect the performance of the next product tested on the same machine. Also, different computers have different software, configurations, etc. that make it more difficult to compare apples with apples. I have researched the built-in derfragmentation tools for Windows. The research is conclusive that with Windows 7, Windows 8, and Server 2008 R2, the performance of the Windows tool is vastly improved over previous Microsoft Operating Systems. With the alternatives, I am fond of the "Optimization" feature and the scripting features available for the command line features of some of the alternatives. Thanks again for your comments!
The Windows 7 and 8 built-in deragmentation tools are much better than those in the previous Windows Operating Systems. Some people prefer the Windows defrag tool, but there are advantages to using an alternate product. Many of the best free alternatives allow you to customize the process to alrge degree. There is even scripting support to help define the way the products perform. Some of the alternatives allow the defragmentation of files that are usually locked by windows. One example is the paging file. Disk optimization is another nice feature of many of these products. Optimization places the files and programs you utilize the most on the outer rim of the drive platters where it is quicker to access. This can help prolong the life of mechanical drives by reducing the movement on the mechanical drives. There is no benefit at all to defragmenting a Solid State Drive. They do not have the moving parts and de-fragmenting will reduce the life span of Solid State Drives.

No, there's not.

Yes, there is, if one button "Defragment" isn't sufficient enough.