"The game crashes if I have mods"
When does it crash? Does it start up at all? Are you using the 32 or 64bit executable? 32 will run out of ram and crash, but the 64 is much more forgiving in that regard.
Playing on Steam version or KSP store version? Have you tried a fresh install? Tried validating your game cache if its steam version?
If the game wont start at all what you need to do is identify the offending mod, and leave it out, or be extra sure that it is updated.
You can:
A) Take all the mods out, run the game to confirm its working, then add the mods back one-by-one until you find the offending mod. Check to make sure that one is updated.
B) Remove your mods one-by-one from the crashing game, starting the game after each removal to see if it will start.