17 Reasons Why Your Mac Runs Slower Than it Should

Has your Mac become as slow as an asthmatic ant carrying some very heavy shopping?
It can happen so gradually at first its hard to notice, sometimes its not until you get to use another machine that it finally dawns on you.

Macs like all computers, can run slower over time, but it doesn’t have to be like this. By performing a few simple clean up and maintenance tricks, you can have it back running like new in no time.

Corrupt Preference Files

Preference files can easily become corrupt and can make programs act weird or run slowly. If your Mac runs slow using a particular application you can try deleting its preference file and relaunching he app (applications create a new file when they are relaunched if they can’t find an existing one). It’s worth making a backup of the old file just i case you lose some settings that are hard to replicate.

preference .plist

Caches, Log files and Temporary Items

It doesn’t hurt to regularly clear out built up Caches, Log files and Temporary Items an easy way to do this is to use an application like OnyX. If you prefer you can delete Caches manually, they can be found in Home/Library/Cache.

Smart Playlists on iTunes

Smart playlists can make iTunes slower as they have to reload every time iTunes is launched. Disable live updating by going to File, Edit Smart Playlist and untick Live Updating.

Too Many Widgets on Dashboard

Each Widget on your Dashboard uses memory, again you can check the memory usage of your widgets by using the Activity Monitor. Remove any used or memory hogging widgets using the Dashboard control panel.


Cluttered Desktop

Having too many files and folders on your desktop can slowdown your machine. Put these files into folders in your home directory and create aliases to them on the desktop.


Wrong Firmware

Using the wrong Firmware can cause all sorts of problems,including making your Mac run slower, keeping your software up to date on a Mac is so easy there is really no excuse. Just click on Software Update in the Apple menu. You can also schedule your Mac to automatically check for updates, go to System Preferences and Software Update and tick Check for updates. You can change the frequency of the checks using the drop down menu.

Software Update

Not Enough RAM

Software can only take you so far. Upgrading your RAM will probably give you the biggest speed increase out of any of these tips. You can use the Activity Monitor application (under Utilities in the Application folder) to check if your Mac would benefit from more RAM. Click on System Memory tab and have a look at the pie chart at the bottom. If the chart is largely red or orange you are running out of RAM. Also take a look at the Page Ins and Outs numbers, if these are continually increasing, its time to upgrade your Ram.
Ram close up

Permission Conflicts

Some issues with applications loading slowly or acting weird can be remedied by repairing permissions. All files in Mac Os X have a set of permissions, these determine which users or applications can have access to them. Sometimes permissions are incorrect and not what the operating system expects. To repair disk permissions you can use the Disk Utility app (in /Applications/Utilities). Select your startup disk and click th First Aid tab, then click the Repair Disk Permissions button.

Disk Utility

Hard Disk Is Nearly Full

Your Mac automatically utilizes free space on your Hard drive as Virtual Memory to free up the RAM. Try to make sure you have 10% free space available for this task.

Lots of Login Items

Removing unwanted or little used programs from your login items. To change your login items go to System Preferences then Accounts and click the Login Items tab.

open at login

Unused System Preference Panes

Clearing out unused preference panes can help free up memory and disk space, check under Other in System Preferences to see what you can remove. You can either disable it in its menu or delete it entirely by removing it from ~/Library/PreferencePanes.

Unused Applications Left Running

All running applications use up your memory and CPU resources, quit applications if you are not going to use them for a while. Some programs have memory leakage issues which means they tend to consume more and more memory the longer they are running it a a good idea to quit and relaunch these every so often.

too many apps

Animated Wallpapers

Animated or slide show wallpaper can really impact the performance of your machine so its a good idea to turn this off.

Browsers Overloaded With Extensions

There are loads of awesome Firefox extensions so its easy to get carried away and add too many. Take a few moments to go through your Add-ons (in Firefox go to tools then Add-ons) and uninstall any you no longer use. For some tips on optimising Safari see my post: Safari Slow? – How To Speed it Up.

add ons

Favicons in Safari or Firefox

You may see an improvement in your browsers performance by deleting your cached Favicons, for Safari just delete the files in /Library/Safari/Icons.


Massive Mailboxes

If you have a massive mailbox with thousands of messages it’s going to take longer to load. Try to delete messages you no longer need and split larger mailboxes into folders.

Mail Activity

Internet Settings

If you are finding your browser slow try clearing the cache and deleting your history. In Safari you do this by going to the main menu and clicking Reset Safari, tick Clear History and Empty the Cache then Reset. In Firefox go to Preferences, Privacy and click the Clear Now button.

Reset Safari


  1. Lynn Ryan says

    Great read. I have been a Mac user for ever. I know about all these items. It is just amazing sometimes how we forget things. You jugged my memory and went back and looked at my mail. I started to open mailboxes. I started to delete many old emails and mailboxes.

    Thanks a lot for the reminder.

    Lynn Ryan

  2. TJO says

    Great post thanks Chris.

    I’ve done a few on the list and my MacBook Pro is definitely running much faster. Using “Activity Monitor” I found lots of apps that I didn’t use running away in the background, but the worst thing slowing my machine down was Parallels, so from now on I will only fire it up with I have to run a windows app.

  3. jmndos says

    So aren’t macs a scam basically……it runs “fast” in the commercial and in the apple stores because they are not actually using them. Once you start using it, it grinds to a halt…..

    More incentive to get a pc……Windows doesnt grind to a halt because of too many icons and neither does ubuntu linux, any distro of debian, or other distribution of linux other than darwin…

  4. Kellie says

    i’m a fairly new mac user and i’ve been looking for a way to speed up my MBP. thanks so much for the tips!

    the only difference that i’ve done is use MacJanitor instead of onyx. thanks again! :)

  5. Mr. Lame says

    This is pretty lame. Seriously… remove icons from desktop, remove cached favicons??? The only things that MAY help are more RAM (if you have less than 3 or 4 gigs), more HD space (do MACs even come with less than 500GB hard drives? – that rules that one out), and apps running in the background. The last is true. All other suggestions can be proven to offer less of a perfomance increase than it is worth concerning yourself of. This article stinks of the banter Windows hacks claim will speed up their crapmachines.

  6. jimmie says

    jmndos: I don’t think it has much to do with the OS. Being a Windows, Mac, and desktop Linux user, I see that the former two camps suffer the same flaw – the user. The machine just gets cluttered. Linux typically runs faster because it’s users are meticulously careful about what the install on it. Most Windows and Mac users aren’t aware, and more importantly, don’t care, what’s on their computer. That is, until it grinds to a halt.

    A lot of my Linux/Mac co-workers have this strange idea that Windows is slower. But it’s typically because they’ve only used spyware, adware ridden non-defragged copies. They don’t know how to protect/clean Windows from those problems. And now we’re seeing the same problem transfer to Macs as they gain popularity. It’s just the user’s fault.

  7. Mr. Awesome says

    Mr Lame, the performance issue with the number of desktop icons is known and technical. Originally in OS X, Apple did not allow users to store icons on the desktop. But the users demanded that Apple bring back this ability. Then the users found out why Apple didn’t allow it originally: Too many desktop icons really does have a performance penalty. So Apple allows it, but most Mac gurus know that you want to keep the number of desktop icons down.

    I know Macs and this article isn’t half as bad as some I’ve seen. Sure, there are a few odd things, like in the comments where someone is using MacJanitor. That was a good idea up until Leopard, when the cron scripts were superseded by launchd tasks…

    “Lots of login items” is definitely legitimate as well. Logging in with the Shift key will show you the difference since it logs in without login items. On my system it makes a difference of 20 seconds or more (because I like my login items, I live with it).

  8. Pat says

    To make a real difference, turn off the spotlight crap (especially its indexing process) and replace it with Quick Silver. The indexing process running in the background is pathetic when you look at the resources it consumes.

  9. Iam Alwaysright says

    my abacus and post-it notes are fast, and never suffer from adware, too many desktop items, etc – forget ubun2, windoes, and applepie, beads-on-a-board + notepad and pencil do it all, faster. oooh PC is better , oooh mac is better, oooh linix is better – GAFL u L7′s

  10. Scott says

    Very nice tips. I also work with Macs and would point out some other details: first, Caches are also located in Macintosh HD/Library/Caches and can also be deleted. Simply select all the files in that folder and move to trash. However, any applications approved for launch by double-clicking a file may have to be reapproved (related to the com.apple.LaunchServices.csstore file), and in Tiger, any fonts in Fontbook that have been temporarily disabled by the user will become re-enabled.

    As well, undiagnosed filesystem errors or corruption can also cause slowness. Use Disk Utility to verify Macintosh HD and if necessary boot to the install disk to repair it, or optionally enter single-user mode by holding [CMD+S] at boot and run a filesystem check by typing “/sbin/fsck -fy”. If the result is anything other than ‘the volume appears to be OK”, repeat the fsck command until it comes clean. There are more advanced ways of running fsck but I won’t go into them here. Type “reboot” to get out when you’re done.

    Also, I would partly disagree with “Mike”, permissions repairs are not voodoo, but it must be remembered that permissions repairs will work ONLY on Apple’s software, it will not resolve any issues with 3rd party programs. Many times I have seen issues resolved with a simple permissions repair (such as applications failing to launch or spinning color wheels generated by starting a task) but only when an issue presents itself as permissions-related after careful troubleshooting and isolation. Only a novice would run permissions repairs frequently or as a knee-jerk troubleshooting step.

    Thanks again for a well put-together post.

  11. Shawn Hickman says

    Great write up. I had my pics going through a slideshow on my desktop. Took that off and things really sped up. Thanks!

  12. Jeremy says

    I was reluctant to get more RAM for my 1gb macbook, but… Running PC games on VMs was getting ridiculously slow, looks like Im springing. That plus a 90% full HD (not including a full external) can start to tax a machine.

    Here is something I found useful for getting back some of the speed you initially when you bought the computer: reinstall osx from time machine. I had a huge slowdown problem a couple of months back and this solved it completely. I did a couple of these things too.

  13. knetboy says

    this is hilarious!
    As an avid PC user, I find that my comp slows down without some degree of “cleanup”, but I thought the Mac users were immune to this sort of thing.
    Wow, and I thought “fanboys” was a state of mind!
    Apparently, we all deal with the same sort of issues.

  14. Jean-Edouard Babin says

    Safari can become very slow, and could freeze few seconds if you have lots of cookies.
    This append because each time you consult a web page Safari write all cookies on disk (it’s not yet using a sqlite database). I had around 4000 cookies and my cookies file was around 7MB. I use a laptop so the hard drive is not really fast and when the disk was just a little busy (when I have mail.app also launched) Safari was spinning. I used http://www.ditchnet.org/cocoacookies/ to suppress arond 3500 cookies, the cookies file is now smaller that a 1MB and safari is really faster.

  15. Pretty computers made by unicorns! says

    Daryn St. Pierre de la Fondue Barghlamonde III Esq. says, “PC users are accustomed to having thousands upon thousands of icons on their desktop and shoved into folders because there is NO REAL ALTERNATIVE WAY of organizing anything (unless of course you use one of those faux Dock applications that are almost always worthless).”

    Ok, if you need more than a file tree to stay organized, you can pretty much call yourself functionally disorganized. This is like saying a kitchen has no means of staying organized because it is limited to drawers and cabinets, and doesn’t have a magic twirling robot that is designed for idiots to find the egg beater.

    Which is really what Apple markets toward: the minority of users who will pay extra for the luxury of idiot-proof technology and a pretty design. What you end up getting is needless complexity. If you’re already organized, you don’t need an extra program to clean up after you. It’s very simple.

    Oh yeah, and the RAM thing. Just go ahead and upgrade. Hah!

  16. borges at KickTime says

    Trouble is that Macs last 5-8 years and run into this kind of trouble. My PC friends have to get new units that don’t just slow down, but stop working in a couple years. Nice ideas and I’ll try a few.

  17. Whitewolf says

    Thanks for the article Chris- I did actually just disconnect the ad ons on firefox a few days ago- I’ll check the recommended program Onyx you have here.
    Do a few other suggestions and let’s see what happens.

  18. phrend says

    Are you sure that un-checking “Live updating” on iTunes smart playlists will provide much of a benefit? I’ve seen other sites that mention this, but none lists any actual testing that proves it. I can certainly follow the logic on this one, but wonder how much CPU each smart playlist query can really consume?

    If you’re right – I’d love a script to toggle the live update setting on all smart playlists so that they only update when I care.

  19. muriel says

    Great post…could relate to PCs as well – and I wondered if the slowness on my Dell as due to Vista///poor microsoft, always getting a bum rap

  20. Jed says

    Seriously, why is it always a PC/Mac debate?

    Whether you buy a Mercedes, a Toyota, or a Ford, maintenance is a part of owning the vehicle. Same with a computer, regardless of the OS. So, why don’t you win guys go read about defraging your hard drive instead of telling us how you never fix your car and get great mileage with 4 flat tires and never changed the oil.

    Safari/Firefox prefs can take care of how much you cache.

    Consider what you really need. Don’t treat your machine like you would shop at the dollar store and consider the source of the software or download that you pull down off the web.

    Poorly created software CAN create security loopholes when it is installed by changing important file permissions and Disk Utility CAN restore file permissions to default values.

    Finally, and this follows the above, take as many applications to the cloud as you can (that’s a cross platform initiative). If there is a choice between software as a service and a widget like client app, go for the cloud service. Let the cloud do the computing for you and keep your own footprint light.

  21. pinecone says

    WHAT? Macs run slow? I thought maccies would NEVER admit to that! I thought only windows ran slow, if you listen to maccies! Nice to see that I am right and that a computer is just a computer and they ALL suffer from many of the same problems, even linux. AND neither is any better than the other. After all, macs use the exact same hardware windows and linux machines use.

  22. johncain says

    jmndos: you must be a retard, seriously. How did you gauge that mac’s grind to a hault from this article? I guess you never used a mac huh? Your pos ass pc will likely crash 12 times through the course of reading this article.

  23. Chris Marshall says

    Thanks for this article, it has extended my to-do list somewhat.

    I used to be guilty of having too may Dashboard widgets and used way too many Firefox plugins. Thinking back I had a number of widgets and plugins that did basically the same thing, how ridiculous!

    Alas, I am guilty of a very cluttered desktop and a single (an very large) inbox in Mail. I blame Spotlight!

  24. Mary Meek says

    I updated my mac computer for the first time in over one month and it is running slow,
    it is almost like the computer is reading my address bar since I did my Mac update Yesterday afternoon…Is that normal?
    Yesterday morning I filled out an application for an ebay learning tool and it had me download something to my computer, I figured it was safe coming from ebay…
    I am confused and not sure what is causing the slowness of my computer.
    I do not even want to use my Mac at this point.
    Do you have ny reccomendations? Or dshould I take it to the Mac store on Monday?
    Please let me know your thoughts on the topic…Thank you!


  25. Southampton Web Design says

    Thank you so much! My MacBook is the only machine I have and I do all my work on it, recently it was getting really slow, fan spinning at 1,000,000 RPM, etc etc.. Went through your list and the one that really sorted it out for me was those pesky Firefox Add-ons..

    Disabled the couple that I don’t need/use that often – and BOOOM – the fan is back to normal and it works like new again!

    Much appreciated.

  26. SLR says

    If your internet is what is running slow, the issue may be with your wireless router or connection. If my internet is slow, I will try cycling my router- turning the router, the computer (and the printer if it is on the same wireless network) off and leaving it off for about 5 minutes before restarting everything. That usually helps.

  27. Losers says

    Seriously!? People need to get a life! So what!! Some people appreciate this article and may not know as much as you arrogant assholes. If it helped them, it helped them. If you don’t like the article or feel the need to come on here and make fun of people who aren’t computer genious like you ” think” you are then move the hell on. No one cares that you “know it all” or that you hate macs or think mac users are in denial that their computers slow down, really just shut up.

  28. Lindsay says

    This really helped me, thanks! I noticed an improvement right away after I cleaned out the corrupt preference files. Thanks again!

  29. Craig says

    This article really really helped me. My Macbook Pro is a great computer but lately it has been really slow. I was planning on doing an entire reformat. After doing a few of the things in this article my computer is back to normal. Im so happy! its running great. Thanks a ton

  30. Bob D. says

    Thank you so much for the article. I followed the directions and cleared the history from my Firefox browser and now it runs as fast as when I first downloaded it. What a relief from all that constant time lag!