Input monitoring chooses to randomly stop functioning in the middle of projects. Anyone ever experience that? It's all fine for while and you can hear what you're playing as you're recording, then all of a sudden input monitoring ceases to function on RECORD only. It's bizzarre. And it's crippling.
Also, that problem seems to park itself in a project once it occurs, and it's universal to the project. Once it rears its head, all tracks have the input monitor disabled on RECORD only. The track records, but you can't hear what you're doing. You can eek by if you know you're really sticking your technique and it feels right, but honestly, that's lame. You can also hear a bit of your playing if your input device allows you to hear the signal direct, and you can pull down ACID's mix to balance, but again, that's lame.
SO, what is corrupting the project file? New ones function fine....for awhile. Some projects escape this fate, some do not. Of course it always seems to occur when you're really in the zone and chasing down something cool.