Defraggler Free (By Piriform Ltd) software review

Disk defragmentation is the process of consolidating fragmented data on a volume (such as a hard disk or a storage device) so it will work more efficiently.

Fragmentation happens to a volume over time as user saves, changes or deletes files. Changes made to a file are often stored in different places on the volume than the original file. Over time, volume becomes fragmented and computer slows down as OS has to look in different places to open a single file.

Disk Defragmenter is a tool that rearranges the data on volume and reunites fragmented data so your computer can run more efficiently.

Defraggler is one of the best disk de-fragmentation software available around and is developed by Piriform Ltd.

Besides Defraggler, Piriform Ltd has developed few awesome software for 'File Recovery' (Recuva), 'PC cleaning' (CCleaner) and 'Checking computer specification' (Speccy). All these software are free for home use but user has to purchase licenses if he wants to use them for business purpose.

I have written this article for Defraggler Free 2.18.945. Future version of software may have different features than those mentioned below. Below are few statistics about software,

  • Version: Defraggler Free 2.18.945
  • System Requirements: 32-bit and 64-bit version of Windows 8.1, 8, 7, Vista and XP excluding RT tablet editions.
  • Languages supported: 43
  • Size: 4.16 MB
  • Size on Disk (Disabled file compress attribute): 4.16 MB
  • Space required for installation: 14.5 MB
  • Is Publisher verified by certified authority: Yes
  • Code Signing authority: VeriSign Class 3 Code Signing 2010 CA
  • Software usage Terms and Conditions for Defraggler Free: Click here
System used for software review
  • 64-bit version of Windows 8 (Single language)

Significance of software code signing
  • Ensure software came from software publisher which is shown in windows 'UAC' prompt (highlighted in below image).
  • Protects software from alteration after publication.
Defraggler installer is signed with code signing authority
UAC prompt for 'Defraggler' installation

Features of software
  • Defragmentation: Defragmentation tool can defragment internal hard disk drives, solid state drives (SSDs) and removable drives (removable hard disks and USB drives). Defraggler cannot defragment data on CDs and DVDs (which falls under removable drives category) as it is read-only. Baseline is defraggler can work with writable media with NTFS, FAT and exFAT format.
    • Disk fragmentation analysis: User can select one or more drives and analyse them for fragmentation. Analysis returns number of fragmented files, number of fragments and fragmentation percentage. User is able to see all fragmented files on particular drive by clicking on 'File list' tab after completion of analysis. User can search fragmented files which are larger than 'n' MB or which are smaller than 'n' MB or contain specific word in filename by clicking on 'Search' tab. If user tried to perform a file search before analysis then software starts analysis automatically and search in file list returned by analysis. User can export list of files under 'File list' and 'Search' tab as '.txt' file. Exported file is a tab delimited file which can be opened in Ms-Excel for viewing.
    • Defrag: User can start defrag for one or more drives after (or without) drive analysis for defragmentation. Defrag takes more time as it considers all fragmented files for defragmentation.
    • Quick defrag: User can start quick defrag for one or more drives after (or without) drive analysis for defragmentation. Quick defrag complete fairly quickly as it does not consider all fragmented file for defragmentation. Default setting for quick defrag is to consider files which have fragments smaller than 50 MB. User can change quick defrag settings to consider fragmented files which are smaller than 'n' MB or have more than 'n' fragments or are larger than 'n' MB or are smaller than 'n' MB.
  • Drive benchmark: User can select a drive and click on 'Benchmark drive' to start drive benchmarking. This operation returns 'Random read speed' for that drive. Higher random read speed of drive indicates that drive performance is good. Random read speed of a drive is inversely proportional to percentage of fragmentation of a drive. Higher percentage of fragmentation of a drive results in lower random read speed and vice a versa. User needs to defrag a drive with low random read speed.
  • Hard disk health: Defraggler scans hard disk health statistics immediately after launch of software. It reports device temperature, buffer size, rotation speed, power cycle count, error rate etc. for the device.

Operating system tools Vs Defraggler
  • Defrag tool:
    • Windows disk defragmentation: Windows disk defragmentation allows user to analyze and defrag similar set of devices as supported by Defraggler. Windows disk defragmentation also allows user to schedule defragmentation of any or all drives daily, weekly or monthly.
    • Defrag tool of defraggler: Defrag tool also allows user to schedule defragmentation but provides option for running it once, daily, weekly, monthly, at system start-up or at logon. Scheduler has option to specify type of defragmentation (Full, Quick, Free space and Free space (allow fragmentation)). User can choose to shutdown system after defragmentation. This tool also shows fragmentation information and drive map for fragmentation. This tool allows drive benchmark and hard disk health features which are not available in windows disk defragmentation.


  • Discrepancies between 'Windows disk defragmentation' information and 'Defraggler' information:
    • Different fragmentation percentage: Both tools show different fragmentation percentage for a drive. This discrepancy suggests that both tools use different methods for calculating fragmentation percentage.
Fragmentation percentage discrepancy between 'Windows disk defragmentation tool' and 'Defraggler' information
Discrepancies between 'Windows disk defragmentation tool' and 'Defraggler' information
  • Defraggler was unable to report problem with removable device driver which prevents it from defragmenting device. Windows defragmentation tool reports device driver correctly with 'Current status' for drive as 'Optimization not available'.
  • Freezing of defraggler: Defraggler freezes if user starts defragmentation for a device which has driver problem.

Dangers of disk defragmentation

  • Data corruption: A defragmentation tool relocates data on a volume by erasing it from one place and rewriting it to another place during a defragmentation process. If computer loses power during a defragmentation process, it can leave parts of files incompletely erased or rewritten. This causes the files to be corrupted and they may not be recoverable. If the corrupted file belongs to a program then that program may cease working altogether. This can be a huge problem if corrupted file belongs to operating system. If an operating system file is corrupted, there's a chance that user has to reinstall the operating system to be able to use the computer again.
  • Data recovery problem: If user has accidentally deleted data from a volume and wants to recover it then first step is to stop any scheduled disk defragmentation for that volume. User should not run disk defragmentation manually for that volume. The reason is that data is not permanently deleted from volume even if user deletes it with SHIFT + DELETE keys on windows. Windows OS removes file handler references but file data still resides on volume. Data recovery tool recovers deleted data by recovering file handlers on volume and then by checking if file content is intact on volume (Not overwritten by any other program). Disk defragmentation tool may use free space in that volume for writing a fragmented file in process which may overwrite file content of deleted files. If that happens then data recovery tool will not be able to recover all data which was deleted accidentally.

Piriform Ltd accepts donations in addition to selling their products for business use. If you are a home user but still want to support their efforts then you can donate to Piriform at donation page.

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