Not as what you thought, it's just hidden, not deleted. If you are into some other Steam games, you will find that there are many hidden achievements for other games. You can still unlock them when you meet the qualifications if they are not broken. Technically speaking, there will be two way how it would end for "Rate a Mod" finally. a) Broken achievement fixed finally, most likely for the situation here, because they've done that before, developer thing b) Broken achievement deleted for good, then there will be 286, no need to worry about, still developer thing, there are some precedents for other games on Steam So what you can do is just enjoying the game and waiting for the result, an update fixing them or an updating deleting them, for the former, do what the achievements ask to or load the saves in this mega thread then you will have 287/287, for the latter, you will just keep enjoying the game however you want regardless of the achievements because you are already 100% there.