yuyhyuh If it's a ship file you can import it directly into blueprint mode, using the hamburger menu in blueprint mode.
Save games are sensitive to changes and tend to break with almost every version because they save extra playgame information and changes or change histories. This is independent from mods but more likely to happen with mods. You can send your save game file to Walt so he can take a look but otherwise there's nothing that can be done about it other than hoping the next game version fixes it.
That's why you always save your ship's design and don't rely on save games.
Anyhow, just to be certain it's not some bug I can fix. Please provide the full log so I can check that off.