OS: Windows 10 (ver 10.0, arch amd64)
Java: 1.8.0_66 (by Oracle Corporation)
Launcher: Minecraft Launcher 1.6.61 (bootstrap 5)
Minecraft: 1.10.1 (updated Wed Jun 22 03:14:48 PDT 2016)
I don't know how it happened but before 1.10.1 it worked and it says that it can't find a block...
MC-103981 Missing BlockEntity (Piston_Extension, ...)