How To Install macOS & Save The Installer

Tim Brookes 23-11-2016

Every year Apple releases a brand spanking new version of its Mac operating system, introducing new features and improvements. These updates are free, and you can even hop on the annual public beta if you’re really keen.


But what if you have a few Macs in your household, and don’t fancy downloading gigabytes of installation files multiple times? One thing Apple doesn’t tell you is how to save the installer, and why you might want to do so.

Fortunately it’s really easy to do, and handy even if you only have the one Mac.

Why Save The Installer?

The most obvious reason you’ll want to save the installer is because of its size. As you’re downloading the whole operating system, rather than an incremental update, the update can be pretty big. macOS Sierra is a 4.88GB download, which is just over 80 minutes at a modest speed of 1MB per second.

Furthermore, if you like to jump on the bandwagon and download the update immediately as it becomes available, transfer speeds can take a tumble as everyone else does the same. When you finally get the installer down, rather than downloading it again on each Mac, you should save the installer instead.

This installation file may also be helpful in the future should something go wrong with your Mac, and you decide to “start again” and reinstall macOS. Despite what many Apple users believe, Macs aren’t infallible and macOS can fail at any time just like Windows can. There are many reasons your Mac won’t wake from its slumber Mac Won't Turn On? How to Fix It and Make It Boot If your Mac or Macbook won't turn on, don't despair. Our guide to troubleshooting all Mac boot problems will get it fixed quickly. Read More , and often the easiest way is to reinstall the operating system using a USB stick.



It’s always best to make this USB stick in advance How to Install macOS From USB Want to install macOS from a USB drive? We'll walk you through this alternative method for installing macOS. Read More , assuming you don’t have another Mac in the house you can use when things go wrong. Keep in mind that if you have to boot into recovery mode to perform the reinstall process, you’ll need to perform this download anyway. It’s best to keep your Mac backed up with Time Machine, and keep that installer handy to save time.

Remember: If you have an older Mac that doesn’t support the latest version of macOS, you’ll need to keep the relevant installation file to hand when it comes to recovering your Mac. You can download this file on any new Mac provided you have it in your purchase history, just open the Mac App Store and hit Purchased.

Download macOS & Save The Installer

Launch the Mac App Store and head to the Updates tab to find the latest version of macOS. You can also find it by searching from it by name, and it also usually appears under Quick Links to the right of the Featured tab.


Download it as you would any other app, enter your Apple ID password, and wait for the process to complete. The installer will automatically launch once the download is complete, but resist the urge to install right away and close it.

Remember: macOS deletes the installer after you’ve used it, so make sure you’ve saved the installer before you update your current machine!


Find the installer file titled Install macOS Sierra (or whatever the current version of the OS is called) in your Applications folder. Copy this installer to a spare hard drive, use it to create a bootable USB stick How to Install macOS From USB Want to install macOS from a USB drive? We'll walk you through this alternative method for installing macOS. Read More , or AirDrop it to any of the other compatible computers Share Files Easily Between Computers With AirDrop & Two Similar Applications [Mac] How often have you sent an email to yourself, simply to move a picture or document between computers? Often, the only obvious alternative is clear overkill, like setting up a temporary FTP server on your... Read More in your household.


Place the Install macOS Sierra file in the Applications folder of any Mac you’d like to upgrade, and run it to perform the upgrade.

Before You Install

Installing a new operating system is a major upgrade, and though most installations will go smoothly there’s always the chance that something will go wrong. For this reason you should always back up your Mac with Time Machine How to Partition Your External Time Machine Hard Drive Here's how to partition an external hard drive for Time Machine on your Mac so you can store other files too. Read More before you update macOS, just in case.

There are precautions to take before you hit Install to minimize the chance of problems — running First Aid on your disk with Disk Utility, ensuring you have enough free space, or creating a USB drive in case things go wrong. We’ve got some guidance if your Mac gives up during the upgrade macOS Sierra Installation Issues? Fix Common Mac Upgrade Problems How do you spot a frozen installation? What if your Mac runs out of space mid-install? And how do you fix the problem when you can't access your computer normally any more? Read More .



The whole installation process takes somewhere around 30 minutes, and when your Mac restarts, you’ll be able to start using your computer again.

What Next?

Choose a Wi-Fi network, sign in with your Apple ID, and agree to the updated terms and conditions to begin using the latest version of macOS. You may also be asked to activate any new features included with the OS, as was the case with Siri on macOS Sierra.

Typically following any major install, you should check for updates via the Mac App Store, particularly as developers get a few months to prepare for the new features. Update any apps that don’t use the Mac App Store separately, most will detect an update and apply it if available. You’ll also want to plug in your Time Machine hard drive and set a new backup point.

If you need to source alternative software because Apple has made that have broken your older apps El Capitan Means The End Of Mac Themes & Deep System Tweaks If you like customizing your Mac, Yosemite might be the last version of OS X that works for you. And that's too bad. Read More , our best Mac software list The Best Mac Apps to Install on Your MacBook or iMac Looking for the best apps for your MacBook or iMac? Here's our comprehensive list of the best apps for macOS. Read More is a good place to start.

Do you have a bootable USB installer tucked away in a drawer somewhere? And what do you think of the latest version of macOS?

Article updated by Tim Brookes on November 23, 2016.

Related topics: Install Software, Mac App Store, Software Updater.

Affiliate Disclosure: By buying the products we recommend, you help keep the site alive. Read more.

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  1. RandyVT
    November 30, 2015 at 3:37 pm

    Why does Yosemite download to the Applications folder? This may be a minor annoyance, but I expect it to download to the Downloads folder. WTF?

  2. Anonymous
    June 29, 2015 at 3:29 pm

    i just upgraded to 10.10.3 but in my purchases tab i still saw the yosemite update and it said download next to it so i clicked it and before i could pause it it had downloaded about 400mb again.. is this an update? it says its the same size as the upgrade was.. is there a way for me to delete the extra 400mb if its not needed as well?

  3. Shona
    April 1, 2015 at 3:05 pm

    I started the install on my year old Macbook Pro at 2am last night. It is 10 am and it is only half way done. There was no warning that it may take this long and I have things to do on my laptop today!! very frustrated. I have no question, just shouting out as a warning to others that LONG download time is a possibility.

  4. Macdew
    March 31, 2015 at 7:49 pm

    If I don't backup my data before installing Yosemite , will my data be lost ?

    • Tim Brookes
      April 1, 2015 at 3:08 am

      No, not at all. It's just possible that something will go wrong when you upgrade, and so creating a backup would reduce any risk of lost data.

  5. Anonymous
    March 19, 2015 at 2:50 pm

    Thanks man!!
    this solved my problem :D

  6. Jalaludin
    February 19, 2015 at 2:57 am

    I lost the installer Where to find it Please

    • Tim Brookes
      February 19, 2015 at 4:35 am

      You will need to download it again from the Mac App Store, which is easy:

      1) Open the Mac App Store
      2) Go to the "Purchases" tab.
      3) Scroll down until you find Yosemite and click the download button.

      It's about 8GB, so it will take a while, but when it's done you can find it as a standalone application in the Applications folder. Copy it to a USB drive or hard drive and put it on any Mac you want to upgrade!

  7. Will
    February 6, 2015 at 10:19 pm

    Thank you for the tip! :D

  8. TechNoob
    January 20, 2015 at 2:51 pm

    If i update to the new OS X Yosemite, will i lose all my photos in the iphoto app?

  9. Cdimaggio
    January 3, 2015 at 8:25 am

    I did not back up Mac before OS X yosemite install. Then there was a power outage during the install. I have not attempted to turn it back on yet. I,m really nervous I will lose all of my pictures if not backed up. What should I do?

  10. Angry Macman
    December 3, 2014 at 12:52 pm

    It completed installation after 56hours. Apparently Yosemite copies all the files in your brew install directory, one by one, and in the more inefficient possible way.
    After booting up (another extra 15min), in about 10mins running well it started with a problem I had before: kernel_task taking over 90% of processors making impossible to use it. The solution -again- was to move out a .plist corresponding to my model.
    Summing up: the installation process was extremely painful because all the waiting, after that it went well.

    • glenelg
      December 16, 2014 at 5:55 pm

      Strange, 56 hours to install. I am running late 2011 Macbook pro 13 with i7 2.8 GHz with 500 Gig SSD Hard drive and 16 gig RAM, all the adobe stuff like Photo shop packages, autocad as well as Logic studio 9. It took my maching 20 minutes to install the Yosemite and once it was up and running, I went and updated all of the above mentioned software updates in under an hour. So far all is running as it should be without a glitch. I don't like the bottom task bar look though, it looks too much like Windows task bar but new system font is a nice refreshing edition.

  11. Ungry Macman
    December 1, 2014 at 8:12 pm

    My current installation of Yosemite didn't finish yet, besides the fact that had been running for (drums) 45 F***ING HOURS. Yes, FOURTY-FIVE HOURS since I dumbly hit the Accept and Continue buttons.
    The installer sucks bad.
    DO NOT UPGRADE TO YOSEMITE UNTIL SOME STABLE VERSION IS AVAILABLE (not the piece of crap that they released).

    • Tim Brookes
      December 3, 2014 at 3:13 am

      Hmmm it sounds like something has gone very wrong there. Assuming you have a recent backup, it might be a good idea to throw in the towel and do a fresh install. I'm sure you'll have no problems after that.

      Yosemite is pretty stable on the whole. though it does have its issues...

  12. Peter Pease
    December 1, 2014 at 6:12 pm

    I installed Yosemite, but now find that it is not yet compatible with other important software I use. I saw nothing above about how to UNINSTALL Yosemite. Can you help me?

    • Tim Brookes
      December 2, 2014 at 12:18 am

      Hi Peter,

      You would have to do a clean install using an old installer for that, I believe. Here's roughly what you'd need to do:

      1. Open App Store, click Purchases, find Mavericks, click download.
      2. Backup Yosemite to Time Machine.
      3. Create a Live USB using the copy of Mavericks you downloaded.
      4. Perform a fresh install using the USB stick.
      5. Restore from Time Machine backup.

      One thing you will want to check is that you can definitely restore a Time Machine backup made in Yosemite to a Mac running Mavericks. I'm pretty confident Apple would make this easy, but it's definitely worth a check.

      Good luck,


  13. Joe
    November 4, 2014 at 12:50 am

    Very helpful thanks!

  14. likefunbutnot
    October 22, 2014 at 6:30 pm

    My users are whining about the new system font. I'd never looked in to it, but sure enough, there's no UI control for changing it beyond the option to reduce transparency effects.

    I can honestly say that there even less to distinguish Yosemite from Mavericks than there is to distinguish Windows 8.1 from the Windows 10 technical preview. Almost all the major new features that did come with Yosemite involve iOS integration and I'm not about to sully myself with that.

    Thanks for finally giving us filesystem access to icloud, I guess?