Sometimes you may need to migrate a UniFi site for which you don't have access to the controller due to server corruption, lost credentials, or a previous installer who didn't provide access.
In this article we will cover several scenarios with steps on how to handle the migration.
No access to device SSH credentials, backups, or UniFi controller
This is the worst case scenario. All the devices will have to be physically factory reset by holding the reset pin, and all network configurations will have to be recreated on the new server.
Network Configuration Migration
In this case you won't be able to migrate any network settings over, so everything will need to be manually recreated on your HostiFi server site.
Device Migration
Without the device credentials, you won't be able to set-inform them. You'll need to hold the factory reset pin on each device to set it back to default credentials of username ubnt, password ubnt, then you will be able to follow the set-inform instructions to adopt the device to the new site you created on the HostiFi server.
You have the device SSH credentials, but no backups, or access to the UniFi controller
In this case, you won't be able to migrate the network configuration, but at least you don't have to factory reset all of the devices by holding the reset pins.
Network Configuration Migration
In this case you won't be able to migrate any network settings over, so everything will need to be manually recreated on your HostiFi server site.
Device Migration
Since you have the SSH credentials for the devices, you can set-inform them to HostiFi without having to factory reset them.
The old controller is offline, but you have a backup
You should be able to migrate the network configuration in this case. Devices may need to be set-inform manually if they don't reconnect to the old controller after you restore from backup, but at least you won't have to hold the factory reset pin on them since you'll have access to their credentials inside the backup file.
First, restore the backup to a UniFi controller on the local network. You could temporarily install UniFi on your laptop for this.
Network Configuration Migration
After restoring the backup, the devices might not reconnect, but you can do the site import/export wizard to move the network configuration. If the devices did reconnect, you can move them with the configuration as well.
Device Migration
If you weren't able to migrate the devices in the site export, you can still get the SSH credentials for the devices from the backup under Settings > Site > (Enable advanced features first) > Device Authentication section, and then you can set-inform them to HostiFi without having to factory reset them.
You don't know the password on the old controller, but you have physical access to it
If you have access to the command-line on the old controller, you can reset the admin password in MongoDB.
Then, you can perform a site migration to move network configuration and devices to your new controller.
You know the password to the old controller, but it's not loading
Try doing a MongoDB prune to reduce the load on the database.
Also, make sure the server has enough storage and memory available, sometimes a hardware upgrade will get it running long enough to migrate.
If you still can't get the old controller up and running, you might need to check for backups and try one of the other migration methods in this article.