I think you’re right. I have 328gb free on my windows install drive, and I have my UE5.1 & Project files both installed to a seperate SSD with 620gb free. For me, this problem happened after I added water to my world and I can only access it when the water plugin is disabled. I recall when I was working on the open world, unloaded chunks that get edited cause immediate crash, but I don’t remember if this was what it said when they did.