Man oh man, that sucks. I had a similar thing happen with my old crockpot and it turned a nice pot roast into a pile of sad meat scraps. The lid had a crack that was barely visible but man it let all the steam out. I figured out my fix by accident when I wrapped the whole top with aluminum foil really tight before putting the lid on. That sealed it up good and the next batch came out perfect. Another thing that helped was cutting the meat into bigger chunks so they don't dry out as fast. Also I started checking the liquid level halfway through and adding a splash of broth if it looks low.

I used to think you had to stick with the original idea or it was a failure, but you just proved me wrong.

My buddy learned this the hard way trying to fix his old ThinkPad with a kitchen knife. Totally agree with @oliverw46, the plastic just shattered under the metal. Now he has a spudger set and a laptop held together with tape.