You can download the Sierra installer in the App Store by searching for “macOS”. Second, you’ll need a copy of the macOS Sierra installer. If this still sounds useful to you, though, read on.

So keep that in mind-you probably won’t want this to be your main macOS system. You definitely want to use a USB 3.0 (or USB-C if you’re using a newer Mac) device, and even then, your system isn’t going to be nearly as snappy as your normal internal drive. For example, your storage capacity is likely to be significantly less than your normal system disk, especially if you use a flash drive.Īlso, speed will be a limiting factor. Of course, while these are some pretty good advantages, there are also some distinct disadvantages. Or you can take it with you to work or a friend’s house while keeping all your applications and files. Maybe you’re having problems booting into your Mac and you want to try to access the internal drive to do some troubleshooting or back up important files-this will let you do that. This allows you to take a fully-fledged macOS installation with you wherever you go, for use on any Sierra-compatible Mac. The method described here actually creates a fully functioning macOS Sierra installation on an external USB device. Keep in mind, this is not the same as using an external device to install macOS, which lets you install macOS from an external USB device. Ever wish you could take your Mac with you on an external drive? You can actually install macOS Sierra on an external drive, flash drive, or SD card, then use that device as your macOS system disk wherever you go.

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