Everything was working fine until I went to load my world yesterday and was informed in a popup that there was a
"Vessel Loading Error" and that "Space Station MK2 was not loaded because it had the following parts missing:
strutConnectorHeavy" I get a similar popup for many of the flights I have around the system, and the game has gleefully made them all vanish. (I have a quicksave, so if there is a way to fix the issue, I can get them back)
I am also not able to open any of my builds in the VAB because they contain a "locked of invalid" part.
I have tried verifying the local content through steam. I have tried replacing the specific listed part in the KW Rocketry parts directory. I am at a bit of a loss.
I am running KSP in 64 bit, and apart from a couple of parts packs and mechjeb, I have no other mods.