Version: 1.0.2 What is the bug: I've been building my base for few weeks until I decided to go explore for resources. I scouted some areas until the client simply crashed. When I tried to relog in the client crashed again. I restarted the server and the client still kept on crashing. Then I asked a friend of mine to log in and go to the same place where my client crashed and his client crashed there as well. So I figured it might have had something to do with the world generation. It may have generated something to the world which is not allowed and that crashed the client. Before I started to remove mods to figure out which mod caused the crash I decided to set the server to peaceful mode. After doing that I logged in with my account and it crashed again, but after logging in one more time it didn't crash anymore and all seemed to be just fine. I think I've seen it before that if I set the game to the peaceful mode and if I then move to an area which had mobs before then they will be visible for a second or so until they are removed from the game. I suppose this explains why the game crashed when I entered it the first time with peaceful turned on. Then I set the difficulty to normal again and continued to explore until the client crashed again, but this time in an area which worked 100% before. I was able to sort out the problem by repeating the peaceful trick. My conclusion is that one of the mods which alter mob behavior is causing the issue. Is this something anyone has seen before? I'll try to figure out which mod causes the issue later today. I'll also provide the error log then. Mod & Version: Paste.feed-the-beast.com log: Can it be repeated: Known Fix: Set difficulty to peaceful for a moment.