After the major 2.3 update, GMS2 has been very unstable and has corrupted about 15 projects of mine. Is why I reverted back to using the trusty 2.2.5 or whatever the old version was. Now I'm using 2.3+ again and hoping to avoid corruptions. I think this is why Game Maker was sold to Opera too, because the 2.3 update brought along more risks with the instability. But yes, it's also a good idea to back up your project versions that still work. I usually have about 10 different versions of my own projects to avoid troubles. It's well known that Game Maker 2.3 is a very risky Beta still. I have my hopes up that some day it'll work as good as 2.2.5 or Game Maker 1.