With some rearrangement of the lab computers, I had plenty of cause to use the Migration Assistant in recent times. It’s usually a smooth process, but I have noticed some flakiness recently.
The most reliable way to transfer files has typically been to make a direct ethernet connection between the machines. Because the Mac automatically handles crossover, you can use any Ethernet cable, and need place no router in between.
I got the message that “connecting a Thunderbolt cable may speed up transfer”, but in my hands, between two thunderbolt equipped Macs, the cable was not even recognised. You might notice that most people praising this method online, haven’t demonstrably tried it.
So be it. The pure Ethernet connection is good enough. However, although I can almost always see the target or source, it isn’t necessarily easy to get past the confirmation codes.
I had recognition problems for other migrations too. An alternate strategy, of making a one-off Time Machine backup of the source machine to a USB disk, and then transferring from that, got stuck at “Preparing source…”. Fortunately, rebooting the target machine helped. Not sure why rebooting mattered- Migration Assistant logs out of the account it is launched from.
Perhaps the problems came from an OS version mismatch? In the latest instance, the source machine was running 10.9 – the best it could manage – it was the first iMac I had in Germany, late 2008 24 inch. The target was 10.12, but trading up has never been a problem before. There’s not much information out there.
Bottom line: Migration is hard to do well (and almost nobody else even bothers). Apple’s solution has been excellent for a decade or more. It’s not all doom and gloom – my own migration into a new MacBook Pro was gracefully handled in a minimum of time. The ability to get back to work in the minimum of time is a major selling point for me. Therefore, I hope these little flickers do not represent a chronic decline in the stability of this key tool in the Mac ecosystem.