Every time I load a new world and start to explore, after a while, minecraft would randomly shut down (shutting down internal server) without a crash report. SO I read the incredibly long log file, and this error was present. (Also there was something about missing textures and an enchantment ID conflict, but when I removed the two conflicting mods, it still kicked me out. The missing textures? I don't know.)
[15:16:25] [Server thread/ERROR]: [DCNotifier] [ERROR] [DummyCoreLoader] C:\Users\IWouldNotShowThisToYou\AppData\Roaming\.minecraft\saves\RandomSeed\DummyData\PlayerData\oOShadowbonnieOo.ddat appears to be damaged, either fix it or delete it!
[15:16:25] [Server thread/ERROR]: [DCNotifier] [ERROR] [DummyCoreLoader] Loading errors were detected at state SERVER_STARTED!
[15:16:25] [Server thread/ERROR]: [DCNotifier] [ERROR] [DummyCoreLoader] The class that has thrown the error: class DummyCore.Utils.DummyDataUtils
This error message was present no matter what world I loaded, even when I created a new world.
I know that it wasn't DummyCore because what it does is it will print out any errors Minecraft has in the log file and crash reports.
The missing textures? There were like a hundred missing textures but I doubt that that was it.
[15:15:19] [Client thread/ERROR]: Error generating texturediamond_ore. Unable to find base texture with same size.
This is the modpack I'm using and I'm the creator.
These are (I think) the mods that spawns any kind of error.
If it works, try re-adding some at each startup until it starts crashing again.
If your crash still happens, also try removing your JVM arguments, replacing it by -Xmx4G -Xms4G -Xmn512m. Also how much ram do you have on your pc ? If you have 8 gigs or more it's ok. Else try allocating less ram (It's not that useful to allocate so much ram in 1.7.10).
And if it still happens, post the log here (also post it on Pastebin or Gist, it's better than mediafire for text files).