Device records are attached to a location record. In relational database language, since multiple devices can be attached to a single location, the location record is considered a “parent” to the device record “child.” Well-designed relational databases don’t allow “orphan” records. To delete a location, first create a new location where you can move the devices. Go to the device file and assign the devices to the new location. When all devices are reassigned you will be able to delete the empty location.