Migration Assistant didn't crash but the iMacs didn't see each other. Maybe I could have solved it by investing time in troubleshooting but it was faster and easier to use firewire.

Jon

macOS 11.7.10, iMac Retina 5K 27-inch, late 2014, 3.5 GHz Intel Core i5, 1 TB fusion drive, 16 GB RAM, Epson SureColor P600, Photoshop CC, Lightroom CC, MS Office 365