If the hopper is connected on the top to automatically input items nothing happens, but if connected from the bottom to automatically output items to a chest, the game crashes. The world cannot be opened after this.

This also occurs with Iron Furnaces, and while I haven't tested, presumably other machines too.

Please don't just say "latest version"

The latest versions 16 hours ago are not the same latest versions now. Please give actual version numbers.

Can i have the log? What versions of reborn core are you using?

Sorry i didn´t put it before, I´m using the last updates of both mods. I send you in a minute the log.

Here are the log and the crash file:
crash-2016-06-12_12.34.55-server.txt
log:
fml-client-latest.txt

The bug is for the following versions:
-Tech Reborn: 1.9.4-1.3.2.120
-Reborn Core: 1.9.4-2.5.3.44
I haven't tested it for newest versions, so I don't know if the bug is already fixed, sorry for the bad call. I will change the name.

I am having a similar issue with all of the latest versions since Tech Reborn-1.9.4-1.3.2.120 and RebornCore-1.9.4-2.5.1.41, although my hopper isn't on an extractor I don't think. Crash Report

I can push a fix for this

Can confirm that this occurs on Iron Furnaces as well. 1.3.2.120 and 2.5.1.41 with forge 1257

Ok I will get an update out soon to fix this

I will upload a new build to curse in a few mins

http://minecraft.curseforge.com/projects/reborncore/files/2307265