I recently made the decision to migrate from the UniFi Cloud Gateway Ultra to the UniFi Cloud Gateway Fiber. Unfortunately, I made the decision to a port on my USW-Aggregation so instead of being a heavily restricted VLAN, it would be the new uplink port for my new UniFi Cloud Gateway Fiber. I saved the settings, swapped the UCG Fiber in after restoring from backup, and learned the hard way that the port didn’t get the updated settings fast enough. This resulted in my core backbone switch getting tagged with “Adoption Failed” and basically requiring a factory reset to solve. I really cannot stress this enough: don’t ad-hoc change these settings and migrate immediately after. I think 30 minutes is probably safe, but make only one change at a time when you’re migrating consoles.

I looked for a good backup / restore path, and here’s what I did: I backed up the old console to the cloud and setup the new console with the WAN port on the LAN of the old console. I did refresh the backup immediately before the move, but I suspect that the backup contained configuration changes the switch didn’t yet have, which is why everything blew up.

I ended up just factory resetting the backbone switch and one AP. Everything else adopted fine.