Thread title is pretty self-explanatory. I did some work on my map in ZE and when I reopened it none of the object changes I had made were there. I figured that I'd just forgotten to save, so I worked on it again and made sure that I saved my progress several times. After closing it and reopening I was angered to find out that it hadn't saved any of my changes. Texture, barrier and plans changes all save (as I discovered after doing some testing) but whenever I add or move objects it doesn't seem to save any of that. Does anyone know what the problem is?

Are any files set to read only? I assume you've already checked, but just to be sure.

No, none of them are set to Read-Only.

EDIT: Alright apparently it was a backup copy of my .wld file that was causing the problem. It wasn't in the world folder but moving it to the desktop seems to have fixed it.