How to install macOS Big Sur on an external drive

You may not want to install the beta version of macOS 11 Big Sur on your Mac as the main operating system and for this there is the option to install the new macOS on an external disk. A) Yes When you want to use the operating system, you can do it completely independently of the official system, which we remember right now is macOS Catalina. For this, it is as simple as downloading the beta version of the new macOS and later installing it on an SSD or pendrive that we will have to have connected to the computer.

macOS Plus (Journaled) on your SSD and erased to install

First of all we have to have the external disk formatted and totally clean since once the system is installed on it, if we do not create a specific partition, the disk or pendrive it will remain exclusively for the system. In this case, my case, I have an exclusive SSD for the system but you can use any disk you have at home taking into account that it is necessary that it meet the GUID partition map scheme. If this is not your case, go to disk utility, select the device that contains the disk, click the Delete button, select "Volume scheme" and click Delete again.

It is possible that if you have the installer open In the process it does not allow you to perform the action of installing on the disk, exit the macOS installer or go with the back arrow and then start the process again so that it detects the SSD to perform the installation.

Once all the previous steps have been carried out, it is like installing the operating system on our Mac but directly on the external disk, it is not complicated by following the previous steps that we have shared in this small tutorial, what is important is to have the external ssd clean and prepared for installation and as we always recommend back up your Mac before installing, even if it is on an external disk.