I have a macbook runnning Catalina. I would like to know if it's possible, when I am booting from an external SSD another version of Catalina to not be able to access the internal drive of the Macbook.
The first idea that comes to my mind would be to turn on Filevault on the internal drive and therefore it will ask for the decryption password on the external alternate operating system. While achieving its purpose, I doubt this is the only solution. Has anyone managed to 'disable' or remove read/write permissions when booting from an external macOS?