How do I reinstall 0.26 update?

So here's what happened:
First, I updated the game through steam, then on the second phase of updating, there was an error saying that theres not enough space, and the 0.26 folder was just pure default copy. No mods and default settings.
It's very hard to explain with words, but here is simplified: steam update button, steam update, steam update complete, open beamng, update window, not enough space window, default beamng copy

 

What do you mean by old stuff?