I have an early 2011 MacBook Pro. I want to try Sierra as most of the software I want to use no longer works on Mavericks. I went through a number of post that I can install Sierra on 8 GB USB drive but that turned out only to be a macOS installer thumb drive.

I am interested in installing Sierra on USB drive just to test drive it and to run my favorite software. I bought 16 GB USB for that purpose but only found out it cannot be installed there for lack of space.

Can somebody guide me, can I have Sierra USB Image that I can load on USB and test drive it or can I install it on USB and run Sierra from it whenever I want it.

  • 3
    Yes, technically you can install and run macOS from a USB drive however on your system it would run painfully slow as the Early 2011 MacBook Pro is USB2. It will also take considerably longer to install to USB then to the HDD. Create a USB Installer on an 8 GB USB Flash Drive and then boot the system with it. Connect a second USB Drive, of 32 GB or larger, at the same time. Then install to the second USB Drive. – user3439894 Feb 19 '17 at 15:18
  • Hmm so why would I need one installer USB and a second one to install on, just curious. Why not directly install it from Mavericks? Also I have SSD installed + have 16 GIGS of ram so my system is very fast! Really no complain there. Yes USB 2.0 could make it slower. – mac_user Feb 19 '17 at 15:25
  • 1
    @mac_user You need an install usb stick because macOS Sierra does not support installing itself (exception: updating) onto other devices except from the bootable installer. Also, the 16gigs of ram is nice, but your USB 2 bus is dog slow and not memory nor processor will do much good. You're only as fast as all of the components working together. SATA for the SSD will only help for in/out filesystem access of files stored on it. A thunderbolt to eSata or USB 3 to an external drive would be practical for testing software. I've done this. – Jonathan Komar Feb 20 '17 at 13:36
  • with that said, I will go ahead and create a new partition on my current drive and install Sierra along side Mavericks from USB. Hopefully it will not affect my other patricians. I have Windows installed as well hopefully it will not affect that. Any thoughts on that? – mac_user Feb 20 '17 at 17:38

You certainly can install macOS Sierra to a USB device. I would advise you use USB 3 or 3.1 in order to ensure a smoother experience while booted from this device.

First of all, use the Mac App Store installer for macOS Sierra, which you can get here: get macOS Sierra. Learn more about obtaining macOS Sierra here: How to download macOS Sierra

Next, it's best to format your USB device as Mac OS Extended (Journaled). With Scheme as : GUID Partition Once you do this, open the macOS Sierra installer. When you are prompted to choose an install destination, make sure to choose your USB device.


Yes, you can. I have installed High Sierra onto a bog-standard Sandisk Cruser 32GB flash drive (2014 Mac Mini). It takes several hours to install with absolutely no output onscreen; I initially thought it had hung. Once booted, its quite usable.

  • Thanks for the answer, and welcome to Stack Exchange. How much space does the OS take on the drive? – Daniel Griscom Aug 4 '18 at 13:50

I too am attempting this on the very same model of machine. I have found that it is possible to install directly to the flash drive without a second USB installer.

However, it took on order of 8 hours to complete. And running the OS was excruciatingly slow. I find this confusing as I have installed that OS on a USB external hard drive with no issues and only a very slight slowdown booting over USB from that drive.

Makes me wonder if Apple is deliberately hobbling flash drive installs. Or perhaps there is some sort of accelerator that is missing for flash drive boot volumes.

  • Do you have ssd or regular harddrive. I don't think it will make much difference though. Thanks for the tip – mac_user Feb 25 '17 at 14:28

Interesting question. Some years ago, I found out, that Snow Leopard is running quite well from USB-sticks or even micro-SDHC with higher reading rate - either via USB 2.0 or 3.0 at MacBook Air and iMacs. This short tutorial shows the procedure.

  • Welcome to Ask Different and thank you for your answer. :) Unfortunately, short answers such as this don't really provide enough detail or context to help many users. And, just providing a link isn't very helpful as it may no longer work in future. Instead, could you please edit your answer (there's an edit link below it) to include a summary of the content you're linking to? This will make your answer more self-contained and help preserve it for other users in future. – Monomeeth Jul 7 '19 at 23:21
  1. Download the High Sierra installer to your Mac (it should end up in Applications)
  2. format the USB pendrive to have GUID Partition Scheme
  3. open Terminal and type: sudo /Applications/Install\ macOS\ High\ Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume --applicationpath /Applications/Install\ macOS\ High\ Sierra.app

Substituting "MyVolume" for the name you gave to your USB pendrive. It will erase the pendrive and install High Sierra on it. Reboot and select the pendrive as the startup disk, using Option key while booting.

  • This does not install the os, this create a bootable USB drive to install the os – rataplan Jul 12 '19 at 0:44

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .