I've had Gamemaker for a while now, and I love it as a game creation tool. I thought it would be fun to enter this jam and make a game.

Now, halfway through the week, Gamemaker just suddenly corrupted the project file of the game I've been working on for the past few days. There seems to be no way to get it back and the only thing to do is restart from scratch, and I'm already behind schedule. This makes me want to switch to something like Unity- What if this were to happen on a much bigger project? That would be disastrous. This whole experience has put a sour taste in my mouth and it's three days worth of work wasted.

Regardless of which engine or tools you use, one thing doesn't change; the need for backups and version control.    Let this be the opportunity for you to set those up, get familiar with them, and live by them.  If you ever lose data, there is only one person to blame... you.

Hope you stick with it.

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.

Hi! I had the same issue a few months ago, so I fixed my project with this tool - YYP Maker. It's free btw. It helped me, I hope it will help you too.  Since then I started to use Git more often ^^

Definitely start using some kind of source control, regardless of what program you're using there is always a chance your data will become corrupted!