Tested and worked today to delete ‘Devices’ (not ‘entities’) manually from .storage/core.device_registry
Just a note for newbies like me. The storage folder is hidden and I had to find it in the mapped folder as I could not see it in HASS.IO file editor (please let me know if there is an easier way).
Very surprised the the entities delete with a button, but not devices.
Same issue can be seen when you setup Plex and have it auto add new connections as it adds them as devices as well. I now have 10-11 devices to manually delete and have disabled auto-adding new device connections.
This is a feature which has been requested for two years at least. Is it on the roadma0 please?
I encounted the problem again. I’m trying to delete a tablet in my home assistant server, to move it to another HA server.
I can open the device in the device page, but there is no option to delete the device completely. I can delete all the entities (after opening every entity separately), but that will only leave me with a device, which has no entities.
Could somebody from HomeAssistant development reply if this function is on the roadmap?
Could somebody check if it’s still possible to delete devices by editing the core.device_registry file? With my instance it’s not working anymore (version 0.113.3)
Its very interesting that there is no response to this relatively simple issue. I’m sure there is more to the issue behind the scenes, but some type reasoning would be better than complaining for years and no response.
Openzwave leaves a lot of junk behind and I would really rather not delete the integration and have to rename these entities AGAIN…
Same thing with SmartThings. I’ve got virtual switches and all sorts of orphaned devices that show up in Home Assistant and just clutter things.
Please allow us to delete individual DEVICES.
Just came here to report the same issue. Like @cree8 said, there’s probably more going on behind the scenes that might make this seemingly simple thing difficult to implement.
Please fix this!
EDIT: You can remove phone devices without deleting the entire category, I just didn’t realize you need to click the device, then click delete. It will not delete the whole category! Just be sure it says “1 device selected” before nuking everything
This is a real plague!!! Allow us to delete devices!! I recently had to factory reset a phone, reinstalled everything, forgot to change the phone name to what it was set to initially and now I’m stuck with a ghost device and a new device. The entity IDs changed but not all entity IDs (WIFI was not recreated and since the ghost device is no longer valid I cannot know on what WIFI network it is connected to). This is a REAL problem and needs to be fixed.
UPDATE : The only way I found to fix this was to remove both integrations for the phone in question that I had to factory reset under Integrations -> Mobile App. Doing so forced me to reinstall the application on the phone, having to configure everything all over again and of course to fix my dashboards. PAINFUL! I hope there will be a better way to do this in the future.
Not sure if this only applies to the mobile app integration, but for me all the devices are considered as individual integrations. This means that on the integrations page they are listed under the same integration, but if I click the options button I can actually delete the integration for that device, meaning that the device is completley removed (enteties and all), but the other devices under the same integration still remains. Checked the core_entities and core_devices and could not find the old Iphone anywhere after I deleted it.
Yes. The mobile app integration is capable of removing one device without removing all. This is how the others should work.
Are there any rules for deleting entries from the \config.storage\core.entity_registry and core.device_registry in 0.115.2? I’ve just bricked my HA trying to get rid of a ghost MQTT device because I wanted to replace a light in my sons room, I mean it is still a light and still in my sons room so why wouldn’t I call it the same name, but can’t as the old entity still exists. Having to roll back now 
I have an Osram Motion Sensor that was behaving weird.
So, naive me was thinking to simply delete it from the integration (deconz/Raspbee) and re-add it.
What a stupid idea!
I ended up with a half-dead device that is - for unknown reason - still somewhat connected to the newly added sensor. What a joy!
Now I tinker in the registry and hope that I do not brick my whole isntallation.
Please allow for an easy way to simply remove a device and its entities.
Update: Looks I did indeed brick my installation. Debugging this will be fun … 
Update2: I failed at debugging and thus had to start from scratch.
The DeConz integration should now be able to remove orphaned devices (after update to 0.116)
I’m running into this issue now that I’ve upgraded my iPhone. I can’t get rid of my old phone as a device and oddly my new one isn’t being connected to the Home Assistant iOS integration.
This fixed the issue for me, thank you so much! 
There is now a service called:
deconz.remove_orphaned_entries
If you go to the integrations page, you can select your old iPhone in the mobile app integration, then hit the 3 dots and choose delete. It will ask you if you want to delete the integration, but in reality it will delete the device you have selected
The mistake I was making wa sconfusing the mobile vs home assistant ios integration (latter being out of date). Once I got that resolve, deleting was straightforward
There is no way that I can find to delete entire devices (not just entities) from an integration. This is a real problem because some integrations (such as RfxTrx) create lots of unusable devices when in auto-discovery mode and then you can’t get rid of them. Please allow deleting devices.
