SetAsync breaking script with no error?

So I'm trying to save this table with tables inside of it with part data but anytime I try to run SetAsyncit just breaks it, I added a spawn(function() and it continues fine but doesn't print or save anything inside of it. This is the second week working on the same problem and quite frankly, I'm pissed.

local PartStoring = game:GetService("DataStoreService"):GetDataStore("TestPartsE")

game.Players.PlayerRemoving:connect(function(player)
    local key = "user_"..player.userId
    --FinalString1 is defined as a table with tables inside it containing part properties and stuff
    print('starting save') --Prints
    if FinalString1 then
        print('Before Saving') --Prints
        spawn(function() --If I don't have this it won't run the rest of the script
            PartStoring:SetAsync(key.."A",FinalString1) --Doesn't save
            print('saved 1') --Doesn't print
        end)
    end
end)