MacAttorney, the FREE Newsletter for Macintosh Using Attorneys


1) If you recently upgraded your Macintosh to a new major version of OS X

2) Restart your Mac

3) Routine Maintenance

4) How Full Is Your Hard Drive?

5) Anti-Virus Programs

6) Dropbox

7) Conflicting Peripherals

8) Test Your RAM

9) Test Your Hard Drive

10) If Nothing Else Works

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 tell you what very likely is not the solution to the 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), 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.

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 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.

1) 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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2) Restart your Mac.  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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3) 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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4) How big is your hard drive and how full is it? 

Rotating Disk Hard Drives

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 problem.   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

"The rule of thumb to keep SSDs at top speeds is to never completely fill them up. To avoid performance issues, you should never use more than 70% of its total capacity."

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

“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. "

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5) Uninstall any third party anti-virus program you have installed.  It's not uncommon for third-party 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.

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6) 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 may be able to work around it 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 Network.

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7) 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.

8) 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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9) 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. 

10) 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.


Unlike a Windows PC, it’s highly unlikely that any sort of malware is causing your slowdown.  However, there has been a rash of adware lately.  You may want to download and run this for peace of mind:

DetectX Swift (currently free, Version 2 will be commercial)

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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:

• Macintosh Routine Maintenance

• Macintosh Beachballs!

• Macintosh Email Software

• Macintosh Word Processors

• Macintosh Accounting Programs

• Upgrading To The Latest Macintosh OS

• Free Or Inexpensive Macintosh Software

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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