Ok, so I guess for some people the 1.3 patch was causing Dead Island to crash on start-up. TheThing2010 posted a response in the game's trainer thread, but if this is a common problem, it may be hard for people to find tucked several pages into that thread. So I'm making a new one with a copy/paste of TheThing2010's answer. All credit goes to him for posting here first (as far as I know).
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Note: Patch 1.3.0 was released for me just now. It was a 1.3 GB update for some and 20MB for others.
Some Steam users are reporting that Dead Island now crashes on startup.
Here's one solution: "Go to C:\Program Files (x86)\Steam\steamapps\common\dead island\DI\Data\game.ini
Locate: Locale('En') and change to Locale('en')"
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[Edited by MediaMaster9000, 10/19/2011 9:44:23 PM]
Just tried it, didn't work at all.