JkDefrag v3.36 Updated

billon on 16 Jul 2018
  • 656KB (uncompressed)
  • Released on 31 Aug 2008
  • Suggested by AlephX

JkDefrag is a low-overhead disk defragmentator with support for multiple optimization strategies. Besides your usual fixed disks, it is also able to defragment removable flash devices in a way that minimizes overall writes. A variety of command-line options for fine-tuned optimization are available. Started without these options, the program activates immediately and defrags all disks.

An interface that gives more control is also available: JkDefragGUI (by Emiel Wieldraaijer). Alternatively, JkDefrag Portable is also available with a custom open source GUI.

System Requirements: Win2K / WinXP / Vista / Win7 / Win8 / Win10
Writes settings to: None
Stealth: ? Yes
How to extract:
  1. Download the ZIP package and extract to a folder of your choice
  2. Delete JkDefragScreenSaver.exe and JkDefragScreenSaver.scr or JkDefragScreenSaver64.exe and JkDefragScreenSaver64.scr
  3. Launch JkDefrag.exe or JkDefrag64.exe. This will automatically defragment all the mounted, writable and fixed volumes on your computer
What's new?
  • Fixed a problem with extremely long path names.

31 comments on JkDefrag  The Portable Freeware Collection Latest Entries Feed

stacoma 2006-12-16 16:39

Works great, but for defrag of floppy disk and removable media you need to add its drive letter to the end of the command path or else JkDefrag automatically will skip these.

Okra 2007-01-31 04:40

Excellet defragmentor program. I like it very much. It can defrage the huge file that many program can not do.

AlephX 2007-02-26 00:05

Hi, Stacoma: look at http://www.emro.nl/freeware/ maybe it is interesting for your needs

Bas 2007-02-26 00:16

Emiel Wieldraaijer from Leeuwarden, Holland made a GUI for JkDefrag:

Bas 2007-04-25 08:02

Also check out Scandefrag:

ScanDefrag is a small windows application that configures Microsoft's, Norton's, or JKessel's disk utilities as part of the next Windows' startup process. This can result in less restarts and cleaner runs of these programs.

Jose Melgar 2007-05-03 07:45

The best defragmenter I can get, in addition is free.
Yesterday I downloaded this program, excellent to install and operate. The GUI interface almost unused is fast and new for me. Congratulations to Jeroen Kessers. Greetings.

Vince_99 2007-06-05 05:53

Integrated JkDefrag for all my drive letters into right-click menu with Fast Explorer (incl. -a 4 command) so defragging any drive (even USB drive) is only one click away

AFOLock 2007-08-27 10:05

re: GUI for JkDefrag - www.emro.nl/freeware

jkdefraggui.exe tries to connect to, port 80
(problabely for checking updates)
Found till yet no workable way to stop it via the Gui itself.
Have contacted the writer of the Gui about it. Maybe we hear from him.

Fred 2007-09-01 02:35

@AFOLock: In JKDefragGUI there is in tab Options, Check for updates on startup.

AFOLock 2007-09-03 08:05

re: GUI for JkDefrag - www.emro.nl/freeware

The layout of the Tab options in the GUI for JKDefrag "can" lead to confusion.
(for those wanting to check - If one (could) thinks its OFF it is in fact ON and vice versa - pls activate your firewall and check for your self the results)

In short -
the author (www.emro.nl/freeware)agreed to workout
a clearer confirmation about the update-status.

I have no doubts that we will see in short time an (minor) update of this otherwise nice GUI.

Richard 2007-10-04 06:15

I see NO REASON to defrag a USB drive. It is random access.

Shodan 2007-10-07 03:33

Absolutely correct about not defragging USB drives, Richard. In fact, USB manufacturers advise against it due to potential damage to the USB chip...

Jerry 2007-10-07 09:49

A USB harddrive is not random access. USB flash drive that are usually formatted to fat32 may need to be defragged as well. I have needed to defrag one when something went wrong in the middle of copying large files.

Jerry 2007-10-07 10:00

Fragmentation on large flash drive can lead to increased risk of failure and defragging can help prevent this. http://www.techworld.com/storage/features/index.cfm?featureid=2814

Simon.T 2007-11-03 13:08

goto C:\Windows\System32 and search for JkDefragScreenSaver.scr JkDefragScreenSaver.exe (so... what is this?)

Rob 2007-11-06 06:35

Just setup the screensaver version and am already in love with this utility. Best defrag program ever!

Re:Simon T. 2007-11-07 15:57

I agree, it creates two files "jkdefragscreensaver" in Windows\System32, probabley a pseudo-screensaver which executes jkdefrag when the computer is idle. So it seems to mean that this is app' is neither stealth nor really portable...

Banshee 2007-11-12 15:03

So dont enable the screensaver, idiot. FFS I am so sick of the "its not stealth" whiners.....

Shit, what if the admins found out you were defragging!!! Man, sackable offence. The app is as portable as you want. Get a life.

JDF 2007-12-03 05:40

This app will remove restore points running under Vista. It is documented in the JKdefrag Forum by several users. No doubt this is a GREAT defragger, but I would caution anyone running Vista to steer clear of it until this bug is resolved. I have personally been burned by it wiping out my Vista restore points, then read that others experienced exactly the same thing.

decomp 2007-12-04 05:20

Not sure if you may call this "a bug" in JKDefrag. Actually, it's The Volume Shadow Copy function in Vista itself that interprets the writing/access actions of JKDefrag as changes of the files, and bloating the storage space for restore points doing so. You probably encounter this problem not on larger disks with larger storage spaces. 15% of 250GB is a lot more then 15% of 80GB!
I agree JKDefrag needs to enhance the program an make it shadow-copy-aware as Diskeeper did as an example. Every defragger "for Vista" has to tacle the hurdle of communication with the Volume Shadow copy Service (VSS).
You're right of course people should be aware of the situation.

Impressed 2007-12-27 17:22

JK Defrag is fantastic. Best defragger i've ever used. Preferred over Auslogics and by far over windows integrated one. Keep up the great work John!

Simon.T 2008-02-03 03:51

RE:Banshee - ROFLMFAO :)

true... true...

Beau 2008-06-29 04:02

I have tried several defraggers and have no idea how well they are doing their job. Just how does one know? I have used Auslogics Disk Defrag non-portable for a quite a while and it is much faster than JKDefrag, which I also run from my hard drive. Is a slower speed an indicator of more thorough defragging?

Shodan 2008-10-01 12:22

Just ran V3.36. It totally removed ALL of my Windows Update history under Vista! Other defraggers do NOT do this. JkDefrag has done this forever, as far as I can tell. PLEASE FIX THIS TERRIBLE BUG!

Wolfghost 2010-11-26 23:07

JkDefrag MyDefrag v4.0 is released !!
The program is now called "MyDefrag"

Magibon 2011-03-14 18:02

Apparently, they no longer offer a Portable version :(

Current version: 4.3.1



Magibon 2011-03-14 18:04

MySQL and uTorrent: known to crash with JKDefrag aka MyDefrag



jamvaru 2012-06-11 19:23

you can achieve greater flexibility by using a batch file to launch your defrag sessions... you could customize individual files for each drive or use multiple configurations for one drive
-here is a short 'script' i use for my removable hard drive with portable apps:

JkDefrag64-3.36 h: -a 3 -f 0 -d 3 -l "h.log" -q

this defragments and optimizes as well as filling in all free space; however, mydefrag is better for a system drive


jamvaru 2012-06-11 19:32

C:\Users\JamesVanRude\Downloads\JkDefrag64-3.36\JkDefrag64 h: -a 3 -f 0 -d 3 -l "h.log" -q

i forgot to test it before i posted it, lol

be sure you get the path right


jamvaru 2012-06-15 17:33

tried it on my portable hd (2tb)
it is ok, but the optimization is lacking; it does some, but not alot
in order to put the portable software first, i put everything else in an 'x' folder and ran the defrag sorting by file/folder...
...then, when the portable apps are in the first position i switched to fill.. but jkdefrag doesnt fill smartly at all, so i switched to mydefrag
... using monthly data defrag and then switching to consolidate i achieved better results... you can do a defrag only alternating with consolidate to get better results
... finally, for a portable hard drive, i recommend defrag only option, as a regular maintenance... in fact, use it as the screen saver, on defrag only, all drives


olliebean 2018-07-16 09:09

This appears to be defunct. The portable version is no longer available to download from the website, and the website for the newer non-portable version no longer exists. v3.36 is still available from https://filehippo.com/download_mydefrag/4595/.


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