The internal drive of my iMac 27″ late 2013 (10.15.8) failed (showed as fragmented). So I want to use an external drive as startUp disk. I successfully installed Catalina macOS in it (timeMachine partitioned APFS volume 1TB), but every time I choose the external drive to be used to boot the PC, it starts the installation process all over again. At the end, it either goes back to using the internal drive to boot or crashes (the “panic” restart) and continues to use the internal drive.
I tried to unmount the internal drive and reboot using the external, and it does the same. Also, I tried to select the external drive from the Startup Disk utility, and it doesn’t appear on the list. Lastly, I tried to install and boot from recovery mode and no luck.
I’m not so knowledgeable on PC stuff, so please help me out.
Thanks!
