The backup and restore functionalities use the accessory serial number and an index of their services to identify and assign accessories automatically. These informations need to be loaded from the accessories and are cached within the app.
At the top of the backups view you can see the status. The app tries to load all needed informations automatically. If all your accessories are reachable and the process completed successfully for every accessory, you will get a green checkmark symbol.
Always check this state before creating a backup or trying to restore from one.
The red exclamation mark symbolizes a problem.
Not all informations could be loaded!
Click the status row to get more details.
This view is showing the rooms and accessories of your setup.
Some accessories may have their services listed as well. This is the case if the accessory contains multiple services of the same type, for example an outlet strip with multiple controllable outlets or a remote with multiple buttons.
Those services have an index that needs to be read too.
As you can see in this screenshot, the accessories are not reachable at the moment and the informations could not be loaded.
After getting them reachable again you can press the read informations button to start the reading process.
You may have disconnected some of your accessories because you need them once in a while or only during a specific season. You should consider to connect them temporarily to read their accessory informations. Once they are complete, you can disconnect them again. That way you would not have to assign them manually within backups.
The green checkmark symbolizes that all accessory informations were loaded successfully.
You can see those informations now inside the table.
If you use the HomeBridge or Home Assistant software to improve your HomeKit setup, please check that serial numbers are unique and exposed by your plugins.