Can You Defrag a Macbook Pro’s Disk or External Hard Drive?

Noticed that your Mac is running slow? You probably think back to the days when you used to own a Windows computer, and how defragging the hard drive speed up your computer’s performance by a lot.

Windows has consistently had disk defragging software. In fact, Windows 7 to 10 naturally defrags on a week after week premise. Apple, however, never included this feature in macOS.

“Why’s that?” you may inquire. All things considered, here are various reasons why Macs don’t offer a defrag work:

  • Macs don’t get the same experience with defragmentation the way Windows PCs are used to.
  • Since the launch of OS X 10.2 in 2002, Macs have been able to defrag automatically.
  • Defragging can cause more harm to the drive because the constant moving of files tires the drive out.
  • If your Mac has an SSD rather than a hard drive, defragmentation will cause no significant benefits and will probably destroy your drive in the process.

In this article, we are going to answer some of the common questions regarding Mac defragmentation, the pros, and cons of this process, and other defragging alternatives you can perform that are safer for your Mac computer. Let’s go!

Why Don’t I Need To Defrag My Mac?

First of all, on the off chance that any of the situations below concern you, we would recommend that defragging isn’t the answer to your concern:

  • Your Mac OS does not predate 2002
  • Your Mac runs on an SSD, not a hard drive.
  • If you are running on Mojave or High Sierra, and your file system has been changed to Apple’s more up-to-date APFS, you won’t have the option to utilize any third-party tools to perform defragmentation on your Mac because there is none available today that work.

Mac’s primary reason why it shouldn’t be defragmented is that the file system, which is HFS+ initially and APFS more recently, does not allow defragmentation since it automatically defrags files if needed.

If a particular file is smaller than 20MB and has more than eight fragments, it will be automatically defragged.

Firstly introduced in 1998, HFS+ could defrag files quickly because of Hot File Clustering. When 2002 welcomed Mac OS X 10.2, the system got even more intelligent at preventing fragmentation.

After a year, Hot File Adaptive Clustering went life, which distinguishes files that are often accessed but seldom refreshed and move them to a particular zone of the drive, defragging them during the process.

In 2017, Apple then announced Apple File System or APFS in High Sierra. At first, it was only available on SSDs, but it arrived on Fusion and hard drives with Mojave in 2018.

It’s similar to its predecessor when it comes to automatically defragment your drive. Still, the way it does the process is a tiny bit different because it creates previews of files so you can open different versions of the same documents.

The companies that created the tools for defragging Macs cry out that Apple didn’t give adequate data about how APS functions or them to be able to have the option to offer instruments to defrag the new file system. For sure, Apple’s reaction to that would be that AFPS does not have any sort of advantage from defragging.

Odds are that if you’re having issues with your Mac, they are most probably unrelated to fragmented files. Fortunately, Mac has various in-app instruments in Disk Utility for troubleshooting, so it’s worth checking out.

When Can I Only Defrag My Mac?

Defragging your Mac is an option for you if and only if the following reasons below applies to you:

  • Your Mac runs on a hard drive, not SSD
  • You are almost out of storage space
  • You are often saving files larger than 1GB

One of the reasons why a hard drive works slowly over time if files are fragmented is because unlike an SSD, it has moving parts, and it needs to move the head around to peruse the various bits of the document you need to access.

If your mac’s storage is less than 10%, then Mac won’t be able to do automatic defragmentation. If this happens, it would be more beneficial for your whole drive if you delete some unimportant documents. Or better yet, do a clean install and wipe your Mac.

On the same point, some users even prefer to perform a clean install before doing a major OS update to improve the performance of their computers drastically. Doing this step will effectively defrag your Mac.

What Are Some Better Alternatives To Mac Defragmenting?

If your mac is not performing as fast as it was before, you don’t really need to complete a defragmenting on your Mac hard drive because most of the time, it’s not your HDD that’s having issues.

That’s why it’s better to try some other solutions that may help you speed up your whole computer without leaning on defragging your Mac.

1. Fixing Disk Permissions

“Try repairing your disk permissions” is one of the most common Mac troubleshooting tips. Permissions are file or document settings that affect the capacity to read, write, and perform the execution of the file. Overtime when they are not set correctly, any software that uses the file may not work as effectively before.

You can repair disk permissions by yourself, but if you don’t want to spend the time doing so, you can opt to rely on an all-in-one utility tool like CLeanMyMac X. Its built-in maintenance module has several options to help you optimize your Mac, such as repairing disk permissions.

2. Update your macOS software

Make sure to always update your Mac to the latest versions because it’s given that every update promises better speed and performance. Most of the time, bug and performance fixes are included in every update, which are common reasons for Mac slowdowns.

3. Delete unneeded files

Ensure that your storage space always has 10% free space so it could perform background actions and give enough space for virtual memory, caches, and temporary files effectively every time.

This task is quite tiresome and repetitive, so it’s more time-effective to entrust CleanMyMac X to perform these types of jobs without a hitch.

Do You Need to Defrag a Mac External Hard Drive?

It’s not necessary to defrag an external hard drive on Mac. However, if you’re looking to perform a similar process on your external drive, here is a foolproof solution that will get your Mac external HDD performing optimally:

Step 1: Get yourself a clean, backup external drive.

Step 2: Copy all the files in the first drive into the second one.

Step 3: Wipe and reformat the original Mac external drive.

Step 4: After reformatting the first drive, copy back the files on the second drive back to the first one.

Doing this process is much safer and safer than the normal defragmenting method. For the reformatting process, you can opt for a quick format on the disk, or even simpler, repartition it into 2 partitions and then back into a single partition. After the process, simply copy the files back.


We hope that this article answers all of your burning questions concerning Mac defragmentation. Again, if you want your Mac to maintain its excellent performance, employ trusted software like CleanMyMacX  to optimize your Mac computer any time!