So since I got 1.0.0, it seems like every time my branch mine is up and running I get the saving chunks crash, but after rebooting minecraft I am unable to continue playing that world, no matter what I try. I've reinstalled java, but that didn't help. This thing has ruined 4 worlds so far. I have many mods installed, none with documented incompatabilies. Is there a fix to this, or is every world I start going to eventually crash forever?
I have 451 GB free, not including drive space reserved for backups. My system specs are too high to be the cause of this crashing. And it doesn't seem like the crash a mod would cause, because there has been no distinct event leading to the crash. It just happens. I'm just digging around and I get saving chunks. Or harvesting wheat, or chopping a tree, or just walking around. It never happened while I was using/placing/breaking a block from a mod.
Put that .minecraft file in a safe place and create a new one. See if the problem is at an outside source (like java).
If not, then I suspect a mod (if you moved it from 1.8 to 1.0) became corrupted during that update process and thus corrupting the way you play Minecraft.
I would check and make sure each and every one of those mods you have are updated for 1.0 compatibility.
Anything to update, always save files, and if all else fails, you will have to create a new .minecraft folder.
I was thinking of a new .jar file and to re-install everything you've got back in there, but unsure if it'll work.