Fixes for an unreadable data.json. Obsidian never throws when a plugin's own data file cannot be read or parsed — it hands back an empty-looking value — so this plugin had been treating "could not read it" as "nothing was ever stored here". Two things could follow from that: an order note whose json block had gone missing could get a fresh empty one written over it, and a settings save could replace a data.json it had failed to read, resetting every setting and dropping the backup copy of your orders.
Now it refuses to write over a file it could not read, and says so. Settings fall back to their defaults with a row in the settings tab explaining that they are defaults and will not be saved, and it recovers on its own once the file is readable again — repair or delete it and the plugin picks it up, or press Read it again. Settings changes are also verified after writing, so a full disk or a read-only folder no longer leaves a toggle that silently disagrees with the file.
Saved orders were never at risk in any of this: they live in the order note, not in data.json.