How to Defrag Hard Drive(s) and Partitions

Hard Disk

This is the second post in a series on “cleaning” your machine. The instructions are for a PC using the free program Defraggler. For a Mac, the best solution is also free: Back up your drive using Time Machine and do a clean install.

Before following this post, refer to the previous post on Delete Junk Files. There is no sense in defragging junk files.

This is for Windows based operating systems


Fragmentation occurs on a hard drive, a memory module, or other media (like SSD) when data is not written closely enough physically on the drive. Those fragmented, individual pieces of data are referred to generally as fragments.

Defragmentation, then, is the process of un-fragmenting or piecing together, those fragmented files so they sit closer, physically, on the drive or other media, potentially speeding up the drive’s ability to access the file.

Why Fragmentation:

Fragments, like you just read, are simply pieces of files that aren’t placed next to each other on the drive. That might be kind of strange to think about, and nothing you would ever notice, but it’s true.

For example, when you create a new Microsoft Word file, you see the whole file in one place, like on the Desktop or in your Documents folder. You can open it, edit it, remove it, rename it, whatever you want. From your perspective, this is all happening in one place, but in reality, at least physically on the drive, this is often not the case.

Instead, your hard drive is probably saving portions of the file in one area of the storage device while the rest of it exists somewhere else on the device, potentially far away… relatively speaking, of course. When you open the file, your hard drive quickly pulls together all the pieces of the file so it can be used by the rest of your computer system.

When a drive has to read pieces of data from multiple different areas on the drive, it can not access the whole of the data as fast as it could if it had all been written together in the same area of the drive.

Over time, as more and more fragmentation occurs, there can be a measurable, even noticeable, slowdown. You might experience it as general computer sluggishness but, assuming excessive fragmentation has occurred, much of that slowness may be due to the time it takes your hard drive to access file after file, each in any number of different physical places on the drive.

A dedicated defragging tool is what you need. Disk Defragmenter is one such defragger and is included for free in the Windows operating system. That said, there are many third-party options as well, the better of which do a considerably better job at the defragmentation process than Microsoft’s built-in tool.


Defraggler is hands down my favorite one.

  • Close all running programs
  • Empty your Recycle Bin
  • Click here for Defraggler Download at from Piriform
  • At the top you see the Download Free Version button
  • Click on Download Free Version. The screen will scroll to the bottom.
  • Click on the Free Download button
  • Click on the Download button. I don’t know why they make this so difficult.
  • Follow the download instructions. Below is an image of what to expect:
Install Defragger
Download of Defraggler
  • After downloading, click the Install button
  • After installation has finished, you are presented with two options: Reboot Now or I want to manually reboot later. For this demonstration, I am choosing the second option.
  • Click the Finish button
  • A shortcut will appear on your desktop

Run Defraggler Analyze

Now we are ready to run the Defraggler program

  • First, restart/reboot your machine
  • Click on the desktop Defraggler shortcut
  • You are presented a screen like my image below
Analyze option

Next highlight a drive other than as SSD drive or flash drive and click the Analyze button. It is not recommended you defrag an SSD drive or a flash drive. These drives have no moving parts. Starting with Windows 7 these drives automatically have a TRIM operation to free up space. If I get a decent response to this post, I will explain how to check to see if TRIM is enabled in a future post.

If the Disk Health does not show GOOD in green you may have a problem. Your hard disk is either bad or is going bad. I recommend closing any open programs and shut down your machine. Kindly take the PC to your local Geek shop, like Geek Squad at Best Buy, and have them take a look at your hard drive. If it needs to be replaced, hopefully, they can copy your data from the old drive to the new one.

Following is my screenshot showing the Analyze results of my drives:

Analyze results

Now I want to show you what the Windows 10 Optimizer stated about the status of my hard drive.

Windows analyze results

There is a big difference on C and D drives. Windows Optimizer says 0%, Defraggler has much different results; C drive is 6% and D drive is 11% defragged. In my experience, Defraggler is the best software to defrag your hard drive(s) and/or partitions.

On my PC, I have one hard drive split into 3 partitions, C, D and E. C is an SSD drive that contains the Operating System. D drive contains all my programs. E drive stores my backup data. (G and L partitions are for my external backup drive.) By doing this, I can easily backup all my data because its only located in one place, the E drive. Windows wants to store your data all over the place. So, if you are buying a new machine, I recommend partitioning your hard drive into 3 partitions and point any program data to the E drive. Install all your programs on the D drive. Some programs give you no options on where to store the program or data; these programs default to drive C. Okay, enough of my soap box drama. Lets continue.

After Analysis is completed, if any drive shows greater than 10% fragmentation, I recommend you defrag the drive.

Run Defraggler Defrag

To run properly, Defraggler needs at least 10% free space on your hard drive. It will run, rather slowly, if there is less than 10% free space available.

Click on the drop down box of Defrag and choose Quick Defrag. This defrag process can take several hours. You can pause or stop the defrag and continue later. I recommend defragging just before you go to sleep; let the program run all night. Also, I recommend you turn off your screen saver before running.

After running, if the fragmentation still shows greater than 10%, then run the Defrag option from the drop down box.

Below is the image after I defragged partition D:

Defraggler results

Notice that partition has no fragmented files. I recommend analyzing your hard drive every 4 months and defragging if necessary. The only sub option I use is the File List to see which files are fragmented.

Remember, your SSD or flash drives will not need to be analyzed/defragged by Defraggler.

Shut down Defraggler and any other running program and reboot your PC.

I Would Like to Hear from You

Please feel free to leave a comment. I would love hearing from you. Do you have a computer tech question? I will do my best to answer your inquiry. Please mention the app and version that you are using. To help me out, you can send screenshots of your data related to your question.


Delete Junk Files


Author: Raymond

I am Raymond Oglesby, an Information Technology (IT) specialist with 30 years in the field. I have taught Microsoft Applications and troubleshot computers in 15 countries and many States. My career was focused on mainframes and desktops from application development to implementation. I have written hundreds of programs for various architectures. I decided to start a blog to share my knowledge and experiences with you. I plan on updating this blog at least twice a week about smart phone apps to Windows. Please feel free to leave a Comment or Tweet. I would love to hear from you. Do you have a computer tech question? I will do my best to answer your inquiry. Please mention the app and version that you are using. To help me out, you can send screenshots of your data related to your question.

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