Could not launch ships or create new campaigns

[CiberX15]

So a few days ago I had a problem where I couldn't launch a ship. The game wasn't giving me any errors telling me the ship was invalid, like too big for the VAB or anything, the launch button was green and made a sound when clicked, it just... didn't do anything.  I removed the wings from that craft and added them back on, and it magically worked. 

Then today I ran into the same issue, but on a tiny craft that didn't even have wings. It was literally just a test craft, a pod, decoupler, and solid booster.  It occurred with every craft I tried to launch so I figured the whole save must be broken. So I exited to main menu and tried to create a new campaign. I was able to set the name flag, etc, but then the begin campaign button did the same thing. It would make the click sound but nothing happened.

I began to suspect something like the save getting too big so I located it in AppData\LocalLow\Intercept Games\Kerbal Space Program 2\Saves\SinglePlayer\ and moved it into a backup and deleted it. 

This did seem to resolve the issue. I was able to create a new campaign and launch crafts with no problem. 

It kind of feels like I ran out of hard drive space, except that the save file was only 10mb, and I have 200+GB storage available on that drive.