JkDefrag GUI


JkDefrag GUI is a graphical user interface program for the open source hard drive defragmentation program JkDefrag.

It enables users to easily use JkDefrag’s powerful defragmentation operations, schedule defrags, perform system file defrag operations on startup, as well as set a wide spectrum of defrag options.

It can also be used to quickly install JkDefrag’s screensaver defrag, an option that kicks in the defrag process and displays it as a screensaver whenever the computer is idle.

I don’t usually think about hard drive defragmentation programs as being exciting, but this one is an exception. JkDefrag itself (rater than the GUI) has a number of features that I have not seen in other free defrag programs, and JkDefrag GUI is a well designed program that makes these accessible and easy to work with.

Here’s a quick listing of some of these:

  • The screensaver option: although JkDefrag does not continuously defragment your hard drive as a process in the background, the screensaver option goes one better in that it kicks the defrag process into action at those idle times when normally your screensaver would run (and will show the visual representation of the defrag process as the screensaver). Extremely cool! This is my favorite feature simply because it provides an automatic install-and-forget solution to hard drive defragmentation. (Note that you can install the screensaver from the ’install’ tab in the GUI).
  • Space hogging files: JkDefrag will push files certain files behind directories and regular files to make system operations faster. These space hogging files include files that are 50 megs+, most compressed archive filetypes, data in the recycling bin, and a number others (for a list of the default space hogging files go to the JkDefrag site and look for “what are spacehogs”). Note that you can use the GUI to manually add more filetypes (e.g. avi, mpg, etc.) to the list of Space hoggers if you want.
  • Portable: a U3-specific version of JkDefrag GUI is available.
  • Safe: ok, so this isn’t a unique feature but a good one to highlight all the same. JkDefrag uses Microsoft’s standard defragmentation API library (which most defrag programs use) and is JkDefragGUI Screenshot - defragmentation visualextremely safe. When interrupted, the defragmentation process will finish the immediate task at hand in the background and shut down.

Aside from these unique features above, JkDefrag GUI provides easy access to powerful defragmentation functions as follows:

  • Easily launch JkDefrag operations: or combinations of operations such as analysis, defragmentation, fast optimization, forcing files together, moving to the end of the disk, sorting files (by name, size, last access, last change, or creation time).
  • Schedule defrags: Allows for scheduling of once-only, daily, weekly or monthly defrags. Also allows for on-startup, on-logon, and on-idle defrag scheduling. Although in general this is nicely implemented, it does NOT seem to allow for scheduling multiple types of events (e.g. on idle as well as, say, every Monday at midnight). It is also not clear how “on idle” is/is not different from the screensaver defrag.
  • System file defragmentation: although JkDefrag does not defragment system files, JkDefrag GUI can schedule these upon reboot (on a regular or one-off basis) using SysInternals PageDefrag utility (included in the JkDefrag GUI download).
  • Set options: set defragmentation speed, disks to defrag (including ’all’), and percent of free hd space to free at the beginning of the disk. Advanced options allow you to determine folders or types or files that you want (or do not want) to be included in the defragmentation process.
  • Set GUI options: including whether to detect removable disks/RAMdisks, shutdown after degfrag, autodetect updates, enable/disable spacehog files option, and others.
  • Installer functions: JkDefrag GUI can be unzipped and run and does not require installation; however, for those who prefer a properly installed app it can install itself as a regular windows app (see the ’install’ tab. It can also be used to easily install the screensaver function). Note that the JkDefrag GUI download contains all the apps/tools that you need, and you do not have to perform any separate downloads.

Other notes/issues:

  • I noticed that this release of JkDefrag GUI always seemed to be taking up some CPU processing resources in the background, even when idle. The author noted that this will be fixed in a future release, which, he noted, will also use less memory.
  • Future releases of JkDefrag GUI will include a disk cleaner and registry defragmentation components (if you want standalone programs that do these functions I recommend CCleaner and Auslogics Registry Defrag, respectively).
  • Tooltips: when in doubt, simply hover over the many buttons with question marks on them and JkDefrag GUI will display a tooltip with info. I found this very useful and wanted to mention it.
  • Another thing I noticed is that when you select “all disks” for defragmentation, the visual representation of the defrag process is not displayed for some reason.

The verdict: this is definitely my freeware hard drive defragmentation program of choice, simply because of such innovative features as the screensaver defrag mode and space-hogging files. JkDefrag is a solid and powerful program that I previously shied away from simply because it was command-line based. With JkDefrag GUI JkDefrag becomes accessible and easy to use. The GUI still needs some kinks ironed out, but these will happen in future releases. I highly recommend it.

Version tested: 0.91

Compatibility: Windows 2000/2003/XP/Vista.

Go to the program page to get the latest version (approx 1.72 megs). Also visit the JkDefrag home page.

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Has been reviewing software since 2006 when he started Freewaregenius.com
  • Thnx for the nice review.

  • I’ve been using JKDefrag since discovering it on your website, and I find it much lighter and faster than the standard Windows defrag. I don’t think I’ll be using this GUI, but it looks great as well. Thoughtful addition by the author.

  • Marc Savoy

    Your site is the most compelling web discovery I’ve made in a long time,courtesy of Download Squad,
    your RSS feed prominently displayed at the very top of my GReader.

    Extra bonus points for the best,cleverest tagline in the history of taglines.

  • I found JkDefrag a few months ago and it is on all my home machines. From Win2k to Xp Home and Pro it is the screensaver on all. You forgot to mention that it won’t start if it has been run in up-to 6 hours and will then launch a normal screensaver of your choice. Highly recommended! I would love to see this introduced into Corporate America cube farms.

  • I have been JKDefrag for months, since before the GUI was available, and have found it to be a staple an all of my machines. I also have this on a LiveCD of WindowsXP that I use to work on customer computers. Fast and free, and extremely efficient. Even marginally better than PowerDefrag with Contig.

  • D Reed

    Downloading pops an Avast warning!! That’s a bit scary. Ideas why it does that?

  • TurboFool

    Seems like a great tool. I’m definitely not fond of how little control Vista gives you over its defrag routine, so I’m downloading this right away.

    I’d love to see a PortableApps version of this one, too. I don’t like/use U3.

  • WC

    Hmmm. I too got the Avast! trojan horse warning when I unzipped – I thought the missiles were coming out of the floor with all the sirens and alarms!! Should we be all that terrified?

  • JuMz

    This trojan warning is a bit concerning…

  • Kissol

    Very good! Um excelente programa para a manutenção do PC no que respeita à desfragmentação.
    O modo Protecção de Ecrã (Screensaver) está adequado para o utilizador ter o seu PC desfragmentado, sem necessidade de ter de se lembrar de o fazer – “instalar e esquecer”.

  • Di Fragga

    there is another GUI available too that might be interesting to compare


  • Juan Rojas

    Please Add: play sound when JkDefrag finished

    Por favor agregar un sonido cuando JkDefrag finalice.

  • Nilson Burgos

    vou testar

  • Anonymous

    How can i download applications in freewaregenius.com?Please reply and tell me.

  • tlm

    9/5/2007 4:50:51 AM,BLINK-MAL-205,Malware,Malware found – W32/Zlob.gen91,Blink has found a malware application,Blink,3.1.1,9,,Virus found=W32/Zlob.gen91;GroupID=61affeb1-2371-4bf1-9440-e422d597aa2d;Item found=C:\Program Files\JKDefrag\JkDefragGUI.exe;Action=Repair;Alert=Yes;Name=W32/Zlob.gen91;Second Action=Quarantine;Category=Trojan;

  • tlm

    I’ve been in touch with Emiel Wieldraaijer, the creator of the GUI, and he assures me that there is no trojan password cracker included in his software.

  • The AV program is probably getting a false positive because the GUI (now on version 0.94) downloads missing files if required. These downloads are legitimate, but many trojans download additional malware when installed, so maybe that’s the reason.

    You can check any “suspicious” file at
    It checks the file against about 20 different scanners, so you get more than one opinion.

    I ran a test on version 0.94 and A-Squared, AntiVir, ArcaVir, Avast, AVG Antivirus, BitDefender, ClamAV, Dr.Web, F-Prot Antivirus, F-Secure Anti-Virus, Fortinet, Kaspersky Anti-Virus, NOD32, Norman Virus Control, Panda Antivirus, Rising Antivirus, Sophos Antivirus, VirusBuster all reported nothing, while CPsecure and VBA32 report versions of “Autoit” trojan/worm. I’m sure these are false positives. Note that AVast no longer identifies it as malware, since they have presumably tested it.

    I have installed and tested the GUI, but still prefer the basic version of JkDefrag because I’m a programmer. I think the GUI is very useful for helping average users to setup things.

    BTW, the JkDefrag program is a “winner” of “The Great Defrag Shootout” which reviewed over 30 commercial and freeware products.

  • thank you

  • Excellent one… i was using it from many days… very fast and lighter one… and most amazing is, no need to install…optimize ur HDD very fast and effectively…

    Btw, ur site is cool man…

    tell if i can have a link exchange with you.

    site: techdudes.blogspot.com

  • allen

    thank you

  • Robert Slade

    Downloaded and unzipped – first thing that happens is that JkDefrag crashes with the “encountered an error” prompt. Great, thanks a lot!

  • Samer

    Robert Slade: “great, thanks a lot?”. Do you think that the world owes you something?

    I don’t get paid if you install the software I write about; this is a free service that takes a lot of my time and all I’m doing here is writing about my experience with the best free software that I find. And I try to do it as best I can.

    Try reading the instructions, or figuring out what it is about your system that causes the error. Otherwise write the author about your experience with their software (or move on).

  • Robert Slade

    OK, point taken, sorry. But I don’t think it’s fair either for you to blame the crash on ‘my system’. I have installed countless applications with no problems, and it’s just a standard XP home OS. It’s frustrating when something crashes straight out of the box like this, even free stuff.

  • RJ

    hey new user (within last hour, thanks to lifehacker.) anyway read ur exchange with Robert Slade and just wanted to say thank you. Thanks for taking the time to do this. Great site and keep up the great work!

  • People are too strict on other people

  • fitznog

    This software should work fine on Win 98 correct?

  • Anonymous

    I don’t see a download link, or a link to the software’s website.

    You write reviews then we have to google them to download? Why not just give a link?

  • Samer

    The link is always the last line in the review, under “compatibility”.

  • CarlT

    Concerning the Trojan Warning:
    I’ve found that if you disable the check for ‘Security Privacy Risk’ in the ‘Extended threat categories’ it no longer reports the EXE file.

  • fotio


  • Avast is infamous for reporting false positives. If you don’t want the warning: change your virus scanner. 😉


  • Another very good freeware defrag program is Defraggler.