> How to migrate from old macOS
What’s the best way to migrate from my iMac running High Sierra to a new M1 iMac?
Although Migration Assistant works best when working between two consecutive major versions of macOS, such as Catalina and Big Sur, it can still save time instead of copying across apps and files manually. For a new M1 iMac, start it up and create its main user account before attempting migration. Then use Software Update to bring macOS up to date. Once you’re happy it’s running sweetly, connect the iMacs back to back using the fastest means possible, preferably Thunderbolt. Open Migration Assistant on each Mac, setting the M1 as the destination, and your old iMac as source. If you can’t get that to complete, go back and be less ambitious about what to migrate until it’s successful. Next, copy across anything you couldn’t migrate, and keep the two Macs running on the same network until you’re happy you’ve got everything.
If you prefer, you can use an app like Carbon Copy Cloner to make a copy of your old startup disk to an external drive, to connect to your new iMac and use as the source for migration. Finally, archive your old backups, and start fresh ones.