Put the summary of the bug you're having here
Was just loading old file of a world I had placed in storage (USB file) I copied the world back onto my computer. Went to view it.

What I expected to happen was...: the world should have loaded to 1.7.9
What actually happened was...:
When I logged onto client and started it back up on 1.7.9 it crashed and I was asked to report a bug. Sorry first time here. Not really a tech

Steps to Reproduce:
1. Load an old file to view 1.7.9 placed in saves
2. ...start client and wait then
3 Client crashed with report...