MacOs Catalina 10.15 - Mac Migration problem from Old Mac to new Mac

The easiest way to migrate from one Mac, to one running a later version of macOS, is to use an up-to-date backup (Time Machine backup or bootable clone backup).

Transfer the backup drive from the first Mac to the second Mac, and point Migration Assistant at the Time Machine drive or the "startup drive". This does not require connecting the Macs directly you could even have wiped the first Mac and gotten rid of it, so long as you have working backup(s). It also is more reliable than migrating over Wi-Fi.

If you are going backwards, then as the others pointed out, you can't use Migration Assistant.

In any case, before you transfer the Mac that you sold to the buyer, be sure to carry out the steps in

What to do before you sell, give away, trade in, or recycle your Mac - Apple Support

The Migration Assistant can't be used to transfer to a computer running an older OS. Open the Sharing pane of System Preferences and use File Sharing instead.

(261522)

Spectre70 wrote:

Hello everyone.

First, I'll write my configuration.

1st Mac --> 2015 iMac i7 MacOS Monterey 10.12 with a USB-connected HD that acts as Time Machine.

2nd Mac --> 2020 iMac i9 MacOS Catalina 10.15

Goal: Transfer files from the 1st to the 2nd.

A bit of confusion here. Monterey is macOS 12, not 10.12.

If the 1st mac is actually Monterey, it appears you are trying to do a backward migration (Monterey -> Catalina). Migration Assistant doesn't do backward migrations.

Or did you actually mean the 1st Mac is running Sierra 10.12 ?

It isn't possible to quickly move the entire profile to an older OS; some preference files may be in a format it doesn't recognize.

(261535)