MacAttorney, the FREE Newsletter for Macintosh Using Attorneys


1) RDHD Reformatted As APFS

2) Too Full SSD

3) Google Chrome Browser

4) If you recently upgraded your Macintosh to a new major version of the Macintosh OS

5) Restart your Mac

6) Routine Maintenance

7) RDHD Too Full

8) Anti-Virus Programs

9) Dropbox

10) Conflicting Peripherals

11) Test Your RAM

12) Test Your Hard Drive

13) If Nothing Else Works

14) Viruses?

Macintosh OS X Slowdown Solutions

                                                        By Randy B. Singer

A very disturbing problem that (fortunately very few) Macintosh users face is a sudden very noticeable decrease in performance of their computer.  This page is designed to help you troubleshoot and fix the problem based on the most likely known causes for this happening.

First, let me say that it is not "normal" for an older Macintosh to decrease in performance. Apple hasn't built-in obsolescence, forcing you to purchase a new Mac.  However, computers do get old and need to have some maintenance done to them to keep them running like new.  Often this can be done for free, or economically.

Next, let me tell you what very likely is not the solution to your slowdown problem.  Has your Macintosh, in the past, with its current hardware configuration, ever performed acceptably?  Is your Mac's decrease in performance a recent fairly sudden occurrence?  If it has and it is, then the common suggestions of many well-meaning folks that your slowdown can be resolved by either (or both) purchasing and installing more RAM, or by purchasing and installing a solid-state hard drive (SSD) (assuming that you don't already have the latter and/or that they are not causing the problem), is misguided.  While those things do increase a Macintosh's performance, they aren't a solution to your underlying problem.  It's like telling someone with a Corvette that is suddenly performing poorly that the answer is to install a turbo-charger.  Sure, a turbo-charger adds performance, but it isn't addressing the underlying problem of what is causing your Corvette, that previously was a rocket, to now be slow.  It's the same with the suggestion that you add more RAM or that you install an SSD.  Those aren't solutions to the specific problem of a sudden decrease in performance (unless the CAUSE of the problem is failing RAM or a too full hard drive).

You need to figure out the source of, and fix, the underlying problem.  Once your Macintosh is back to normal you can decide if it is worth paying for hardware upgrades that improve stock performance.

Note that the following are the most common causes of a sudden/recent slowdown.  There are other, less common causes, but it is worth ruling out all of the likely causes first.  At the bottom of this page, if all of the common suggestions fail, I will tell you how to track down less common problems.


If you have an older Macintosh, and it has an internal (startup/boot) rotating disk hard drive (RDHD), and it came with macOS 10.13 (High Sierra) or earlier, and then you upgraded your Mac to macOS 10.14 (Mojave) or later, your RDHD was automatically and non-optionally reformatted using Apple's new hard drive format APFS (the old format was HFS+) as part of the upgrade process.  APFS is optimized for SSD's.  Unfortunately, it is non-optimal for RDHD's, and it will turn your RDHD forevermore into a dog performance-wise.  You will see lots of rotating beachball cursors and have long waits whenever your Mac has to access your hard drive, especially when launching applications or starting up your Mac.

You can read about why APFS and rotating disk hard drives (RDHD's) don't really work well together here:

Using APFS On HDDs ... And Why You Might Not Want To

From Mike Bombich (of Carbon Copy Cloner fame):

"I'm convinced that Apple made a fundamental design choice in APFS that makes its performance worse than HFS+ on rotational disks. Performance starts out at a significant deficit to HFS+ (OS X Extended) and declines linearly as you add files to the volume.
"The other time that the performance difference will be starkly noticeable is when you're booting macOS from a rotational HDD. macOS seeks and stats thousands of files during the startup process, and if that's taking 15 times longer on a rotational disk, then your 30-second startup process is going to turn into 8 minutes. When the system does finally boot, the system and apps will still feel sluggish as all of your applications load, and those applications each stat hundreds of files. The system is still usable, especially as a rescue backup device, but it's not the kind of experience you'd want for a production startup disk nor for a high-stress restore scenario."
An analysis of APFS enumeration performance on rotational hard drives

Once your RDHD is formatted as APFS, it IS possible to revert back to HFS+...but it's a pain to do so.



Many folks throw up their hands and just replace their RDHD with an SSD.  Others, with older Macs, tend to take the opportunity to upgrade to a new Macintosh.

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When Apple first started offering SSD's instead of rotating disk hard drives, they were enticing for their additional performance, but they were an expensive option.  To partially offset the increased price of choosing an SSD, many folks purchased the smallest (i.e. cheapest) SSD option, or at least an SSD that was much smaller than was optimal.  Unfortunately, at this point most of those folks now have SSD's that are quite full.  Even worse, "quite full" for an SSD might mean that your SSD is so full that it has just about reached the end of its useful life.  This has presented a nasty performance problem for folks who have held on to their Macs for more than a few years.

"In practice, an SSD’s performance begins to decline after it reaches about 50% full."

"When you get close to the 70% threshold, you should consider upgrading your computer’s SSD with a larger drive."

"SSDs may suffer performance issues, especially in writing speed, when the drive reaches full capacity. It is easier for the drive to write to an empty cell when there is free space available. When the drive is full, the SSD needs to find out which blocks are partially filled, move that information into a cache and then write it back to the drive. It is best to have 10-15% of your drive set aside for free space, to keep a good balance between performance and space utilization."

You can't simply trash (delete) apps and files to free up space on an SSD that is too full to cure the slowdown problem.  Doing so only marks the registers that they occupied as available, it doesn't erase them. To make matters worse, there are no tools available to "secure erase," or erase the available free space of, a Mac SSD.  Apple's Disk Utility used to have this feature available for rotating disk hard drives, but it isn't there for SSD's. 

"With a solid-state drive (SSD), secure erase options are not available in Disk Utility."

For older Macs with SSD's that have slowed down precipitously because they have become too full, you basically are faced with your only option being to replace your SSD with a newer, bigger one.

For Apple Silicon-based Macs (e.g. M1, M2, etc. based Macs), since the internal SSD is an integrated part of the SOC (system on a chip), and hence the SSD is not upgradeable, your choices are basically to replace the motherboard, or to get a new Macintosh.  (This isn't due to some conspiracy that Apple has plotted against you.  It's because integrating the SSD, RAM, and other functions all into the SOC is one of the big ways that Apple has been able to make their Apple Silicon processors so wildly fast.)

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Google Chrome sometimes installs a file called "Keystone" on your computer, which is correlated with massive unexplained CPU usage.  It can make your whole computer slow even when Chrome isn't running. In these instances, deleting Chrome and the Keystone file can drastically improve your Mac's overall performance.

If you are using Google's Chrome browser, you may want to consider ditching it (along with Keystone) and using a different browser if you've noticed that your Mac isn't as snappy a performer as it used to be.  See:

How to: Remove Google Chrome & Keystone Completely on Mac OS

Chrome (and Keystone) can't be uninstalled just by dragging Chrome's icon to the trashcan.  Chrome embeds a bunch of files deep into your Mac's operating system.  I like using this free search utility to find and uninstall all of Chrome's files:

EasyFind (free)

These are the files that you need to look for and delete, in addition to trashing Chrome's icon and/or folder:

~/Library/Application\ Support/Google/Chrome/
~/Library/Application\ Support/CrashReporter/Google\ Chrome*
~/Library/Preferences/Google\ Chrome*
~/Library/Saved\ Application\ State/
~/Library/Google/Google\ Chrome*
~/Library/Speech/Speakable\ Items/Application\ Speakable\ Items/Google\ Chrome/
~/Applications/Chrome\ Apps*

If you liked Chrome, the Brave browser is basically Chrome (it uses the same open source codebase as Chrome) with all of Google's spyware stripped out.  It also has ad blocking and a bunch of other nice security features built-in.  It doesn't suffer from the Keystone slowdown problem:

Brave browser (free)

The Brave browser is currently the most secure browser for the Macintosh (using standard settings).  It's quite a bit more secure than Safari.

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If you recently upgraded your Macintosh to a new major version of OS X, it’s going to be slow for a day or two while Spotlight re-indexes your hard drive.  This is normal. (You can verify that this is the case by putting your drive into Privacy mode in Spotlight's System Preferences panel.  But that shouldn't be necessary.  You know if you have just upgraded your Mac's OS.  You just need to be patient for a couple of days.)

If you normally shut your Mac down at night, you may instead want to just leave it on all night for a few days so that Spotlight can do its thing. 

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Sometimes this is all it takes.  Restarting your Mac will cause all of your applications to quit and it will clear your Mac's memory.

Click on the Finder icon in your dock, then choose: Apple menu --> Restart.

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Maybe some quick routine maintenance will help.  Have a look at this Web site and do all of the relevant routine maintenance:

Mac OS X Routine Maintenance

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Rotating Disk Hard Drives

Macs with rotating disk hard drives (RDHD's) (which at this point are mostly older Macs) run terribly when they don't have enough free contiguous hard drive space to work with for caches, databases, virtual memory, etc..  If your hard drive is approaching, or is over 80% full, this is likely the reason for your Mac's slowdown.   You will either need to clear a lot of data off of it, and then defragment your hard drive, or you will need to get a new, bigger hard drive.


Macintosh OS X Routine Maintenance
Have a look at both item #5 and Note #1

Solid State Hard Drives
See Item #2, above.

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Uninstall any third party anti-virus program you have installed. It's not uncommon for third-party fully interactive anti-virus programs to cause software conflicts which will bring your Mac to its knees.  Third-party anti-virus programs typically have to be uninstalled using either specific instructions, or an uninstaller program that you get from the program's developer.  They can't be fully uninstalled by dragging their program icon or folder to the Trash.  I have found that Sophos Antivirus is most often the offending program here.  Users are attracted to it because it is free.  But this is one of those cases where "free" may not be a good deal.

How to uninstall Sophos Antivirus Home Edition:

After you uninstall your anti-virus program, restart your Mac and see if things are better.

NOTE: The above only applies to fully interactive anti-virus programs.  A fully interactive anti-virus program is one that is always running and which automatically checks new downloads.  The above does not apply to anti-virus programs designed to work only when you manually launch them and run a scan.

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If you use Dropbox, quit the program:
Go to the Dropbox menu --> choose the gear icon on lower right --> choose Quit.
If this solves the problem, you have just proven that Dropbox is the source of your slowdown. 

You may be able to work around a Dropbox slowdown by limiting the bandwidth Dropbox uses when it is enabled.  Go into Dropbox Preferences (in the Dropbox menu, choose the little gear icon in the lower right) and then choose Network.

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Disconnect all peripherals (especially USB hubs) other than the Apple-supplied keyboard and mouse and restart.  If you are using a third party keyboard and/or mouse, temporarily replace them with the original Apple-supplied ones.  See if that fixes things.  If it does, you can reattach one peripheral at a time and restart your Macintosh after attaching each one to see which peripheral is causing the problem.

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If none of the above is the problem, it’s time to rule out bad RAM or a failing hard drive.


Test your RAM with:

Apple's Hardware Test/Apple Diagnostics:

Hardware Test is for June 2013 and earlier Macs; Apple Diagnostics is for more recent Macs.

Apple's Hardware Test (AHT):

Apple Diagnostics

However, Hardware Test and Apple Diagnostics don't do as thorough job as they could with respect to testing your RAM.  (However, they are worth running for other reasons.)  A "failing RAM" report will be accurate, but a passing result may not be.  More thorough would be:

Rember (free)
Run it and see what it says.  Typically the problem will be due to non-Apple RAM.  Remove bad RAM and return it to the supplier for replacement.

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Test your hard drive with:

The free demo version of the following will comprehensively tell you how well your hard drive is doing (though I don't know how well it works with SSD's):

DriveDX - free demo

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Still no joy after trying all of the above?  Try this diagnostic procedure to see if you can zero in on the offending application. 

Launch Activity Monitor (in your Applications/Utilities folder), and click on the "%CPU" header.
Then click on the triangle in the %CPU header so that things are ordered in that column from most to
least.  See if anything is running that is using an inordinate amount of CPU time.  If something
has a really high number, this is likely to be what is causing your slowdown.

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Unlike a Windows PC, it’s highly unlikely that any sort of malware is causing your slowdown.  However, since you can comprehensively test for malware (and remove it, if necessary) using free, easy to use utilites, you might as well check just for your peace of mind:

VirusBarrier Free Edition (free)
This is a full version of Intego's commercial anti-virus program VirusBarrier [usually $40/year] minus some [but not all] of the automated scanning features in the commercial version.  Since this version isn't fully interactive, it won't create any slowdown problems with your Macintosh.

Note that AV programs, and the Mac OS, do little or nothing to combat adware.   So, in the rare event that you are confronted by adware, you may want to download and use:

DetectX Swift (free)

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If you have any additions to this Web site to suggest
I would very much appreciate hearing your suggestions.
Send them to:
Randy B. Singer

Other Web pages by Randy B. Singer that might be of interest to Macintosh users:

Free Macintosh Software

Macintosh Time & Billing Software

Macintosh Law Office Management Software

• Macintosh Routine Maintenance

• Macintosh Beachballs!

• Macintosh Email Software

• Macintosh Word Processors

• Macintosh Accounting Programs

• Upgrading To The Latest Macintosh OS

About The Author Of This Web Site

Randy B. Singer is:

- The head of the MacAttorney User Group
with, at this writing, close to 10,000 members!

- A co-author of The Macintosh Bible (4th, 5th and 6th editions);

- Author of the ABA publication:
The Macintosh Software Guide for the Law Office

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