How to install macOS on an external drive
Worried about installing macOS Big Sur on your Mac? Don't want to run Big Sur as your main system? Run it on an external drive.
| 04 Mar 21
If you're worried about updating your Mac to macOS Big Sur or Catalina (perhaps due to incompatible software), or if you are testing a beta version of macOS Big Sur and don't want to risk messing up your system, you don't have to install the update on your Mac at all - you can install it on an external hard drive instead.
Installing the Mac operating system on an external drive is the safest way to get a good look at a new OS without changing anything on your Mac. It'll leave your current configuration intact and allow you to play around with Big Sur or try out the beta of the next version of macOS.