I created the world back in 1.8 i believe. when I logged on in the new 1.10.1 the game immediately crashed giving the following reports. Could not recreate in other worlds. but happened 6 more times in the first world. Returning to 1.10 the problem stopped.

---- Minecraft Crash Report ----
// Ooh. Shiny.

Time: 6/22/16 10:09 AM
Description: Server forgot to send required information to construct BlockEntity

java.lang.RuntimeException: Missing BlockEntity
at bqy.b(SourceFile:162)
at bqu.a(SourceFile:100)
at bqu.run(SourceFile:43)
at java.lang.Thread.run(Thread.java:745)

A detailed walkthrough of the error, its code path and all known details is as follows:
---------------------------------------------------------------------------------------

– BlockEntity missing instance data –
Details:
BlockState: minecraft:piston_extension[facing=east,type=sticky]
Block coordinates: World: (106,67,55), Chunk: (at 10,4,7 in 6,3; contains blocks 96,0,48 to 111,255,63), Region: (0,0; contains chunks 0,0 to 31,31, blocks 0,0,0 to 511,255,511)

– Affected level –
Details:
Level name: MpServer
All players: 1 total; [bnn['rcnerd'/434, l='MpServer', x=46.44, y=147.88, z=172.11]]
Chunk stats: MultiplayerChunkCache: 1089, 1089
Level seed: 0
Level generator: ID 00 - default, ver 1. Features enabled: false
Level generator options:
Level spawn location: World: (-4,64,144), Chunk: (at 12,4,0 in -1,9; contains blocks -16,0,144 to -1,255,159), Region: (-1,0; contains chunks -32,0 to -1,31, blocks -512,0,0 to -1,255,511)
Level time: 7367680 game time, 9504115 day time
Level dimension: 0
Level storage version: 0x00000 - Unknown?
Level weather: Rain time: 0 (now: false), thunder time: 0 (now: false)
Level game mode: Game mode: survival (ID 0). Hardcore: false. Cheats: false
Forced entities: 84 total; [yk['item.tile.cloth.white'/385, l='MpServer', x=84.52, y=61.00, z=127.13], yk['item.item.muttonRaw'/386, l='MpServer', x=84.13, y=61.00, z=127.88], zg['Spider'/1410, l='MpServer', x=-4.50, y=18.00, z=217.50], wl['Sheep'/387, l='MpServer', x=91.46, y=67.00, z=173.78], wn['Squid'/131, l='MpServer', x=19.45, y=62.48, z=142.75], zi['Zombie'/1411, l='MpServer', x=-1.50, y=18.00, z=217.50], wn['Squid'/132, l='MpServer', x=23.26, y=60.71, z=145.72], wd['Chicken'/388, l='MpServer', x=105.88, y=63.09, z=109.58], zi['Zombie'/1412, l='MpServer', x=-2.50, y=18.00, z=215.50], wn['Squid'/133, l='MpServer', x=24.59, y=60.81, z=151.22], yk['item.item.egg'/389, l='MpServer', x=106.88, y=62.00, z=108.62], zi['Zombie'/1413, l='MpServer', x=-3.50, y=18.00, z=219.50], wn['Squid'/134, l='MpServer', x=21.01, y=62.01, z=151.85], wl['Sheep'/390, l='MpServer', x=98.14, y=65.00, z=125.62], zn['Villager'/135, l='MpServer', x=20.44, y=62.50, z=169.82], zg['Spider'/391, l='MpServer', x=111.50, y=68.00, z=122.50], zn['Villager'/136, l='MpServer', x=17.37, y=62.42, z=184.74], wl['Sheep'/392, l='MpServer', x=111.30, y=71.00, z=165.21], yp['Creeper'/137, l='MpServer', x=17.50, y=45.00, z=221.50], wl['Sheep'/393, l='MpServer', x=101.52, y=66.00, z=201.26], wa['Bat'/138, l='MpServer', x=22.20, y=42.10, z=225.38], wn['Squid'/139, l='MpServer', x=17.51, y=56.78, z=221.80], wl['Sheep'/395, l='MpServer', x=114.30, y=71.00, z=168.50], wl['Sheep'/396, l='MpServer', x=120.82, y=70.00, z=180.55], wl['Sheep'/397, l='MpServer', x=125.18, y=71.00, z=192.69], wi['Pig'/37, l='MpServer', x=-21.36, y=67.00, z=105.99], zd['Skeleton'/38, l='MpServer', x=-21.50, y=67.00, z=100.50], wi['Pig'/39, l='MpServer', x=-31.74, y=65.00, z=117.89], yp['Creeper'/40, l='MpServer', x=-31.79, y=67.00, z=115.53], zi['Zombie'/41, l='MpServer', x=-20.50, y=48.00, z=175.50], zi['Zombie'/42, l='MpServer', x=-20.50, y=48.00, z=175.50], zi['Zombie'/43, l='MpServer', x=-19.50, y=48.00, z=179.50], zd['Skeleton'/48, l='MpServer', x=-6.50, y=51.00, z=166.50], wa['Bat'/49, l='MpServer', x=-7.58, y=51.03, z=165.98], yp['Creeper'/50, l='MpServer', x=-11.50, y=52.00, z=173.50], zd['Skeleton'/51, l='MpServer', x=-13.50, y=52.00, z=175.50], zd['Skeleton'/52, l='MpServer', x=-13.50, y=52.00, z=177.50], zd['Skeleton'/53, l='MpServer', x=-14.50, y=52.00, z=176.50], yp['Creeper'/54, l='MpServer', x=-1.50, y=39.00, z=210.50], zd['Skeleton'/950, l='MpServer', x=43.50, y=42.00, z=187.50], wl['Sheep'/55, l='MpServer', x=6.51, y=67.00, z=93.72], zd['Skeleton'/951, l='MpServer', x=44.50, y=42.00, z=186.50], zi['Zombie'/56, l='MpServer', x=6.03, y=48.00, z=192.32], zd['Skeleton'/952, l='MpServer', x=42.50, y=42.00, z=187.50], zn['Villager'/57, l='MpServer', x=8.16, y=63.30, z=200.55], wn['Squid'/58, l='MpServer', x=16.93, y=60.04, z=223.51], wn['Squid'/59, l='MpServer', x=11.16, y=57.73, z=221.69], zd['Skeleton'/60, l='MpServer', x=6.50, y=52.00, z=210.50], wn['Squid'/64, l='MpServer', x=6.44, y=58.74, z=222.08], wn['Squid'/197, l='MpServer', x=34.35, y=60.00, z=147.44], yk['item.tile.mushroom'/1093, l='MpServer', x=100.98, y=65.00, z=202.38], yk['item.tile.flower2.poppy'/198, l='MpServer', x=34.69, y=60.00, z=174.50], zn['Villager'/199, l='MpServer', x=47.70, y=155.00, z=171.70], zn['Villager'/200, l='MpServer', x=47.70, y=155.00, z=171.30], zn['Villager'/201, l='MpServer', x=45.30, y=155.00, z=171.70], zn['Villager'/202, l='MpServer', x=46.39, y=155.00, z=171.41], zn['Villager'/203, l='MpServer', x=45.30, y=155.00, z=171.70], zn['Villager'/204, l='MpServer', x=35.70, y=155.00, z=182.70], zn['Villager'/205, l='MpServer', x=35.30, y=155.00, z=181.70], zn['Villager'/206, l='MpServer', x=35.70, y=155.00, z=182.70], zn['Villager'/207, l='MpServer', x=35.30, y=155.00, z=181.03], zn['Villager'/208, l='MpServer', x=46.49, y=155.00, z=193.70], zn['Villager'/209, l='MpServer', x=47.70, y=155.00, z=193.30], zn['Villager'/210, l='MpServer', x=45.88, y=155.00, z=193.30], zn['Villager'/211, l='MpServer', x=47.70, y=155.00, z=193.70], zn['Villager'/212, l='MpServer', x=46.49, y=155.00, z=193.30], zn['Villager'/213, l='MpServer', x=45.30, y=155.00, z=193.30], zn['Villager'/214, l='MpServer', x=47.09, y=155.00, z=193.30], wn['Squid'/215, l='MpServer', x=47.09, y=60.17, z=209.60], wn['Squid'/216, l='MpServer', x=44.30, y=60.43, z=215.81], wn['Squid'/217, l='MpServer', x=48.97, y=61.19, z=212.75], wn['Squid'/218, l='MpServer', x=49.40, y=61.17, z=225.76], zn['Villager'/371, l='MpServer', x=57.70, y=155.00, z=181.95], zn['Villager'/372, l='MpServer', x=57.70, y=155.00, z=181.30], zn['Villager'/373, l='MpServer', x=57.30, y=155.00, z=183.11], zn['Villager'/374, l='MpServer', x=57.70, y=155.00, z=183.70], zn['Villager'/375, l='MpServer', x=57.30, y=155.00, z=181.30], zn['Villager'/376, l='MpServer', x=57.30, y=155.00, z=182.48], wn['Squid'/379, l='MpServer', x=66.65, y=61.87, z=143.75], wn['Squid'/380, l='MpServer', x=72.63, y=61.35, z=143.66], bnn['rcnerd'/434, l='MpServer', x=46.44, y=147.88, z=172.11], wn['Squid'/381, l='MpServer', x=64.69, y=62.32, z=149.66], wn['Squid'/382, l='MpServer', x=70.61, y=62.40, z=146.63], wl['Sheep'/383, l='MpServer', x=75.29, y=63.00, z=205.54]]
Retry entities: 0 total; []
Server brand: vanilla
Server type: Integrated singleplayer server
Stacktrace:
at bln.a(SourceFile:364)
at bcx.b(SourceFile:2535)
at bqu.run(SourceFile:49)
at java.lang.Thread.run(Thread.java:745)

– System Details –
Details:
Minecraft Version: 1.10.1
Operating System: Windows 10 (amd64) version 10.0
Java Version: 1.8.0_25, Oracle Corporation
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
Memory: 4847101920 bytes (4622 MB) / 6174015488 bytes (5888 MB) up to 6174015488 bytes (5888 MB)
JVM Flags: 3 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx6G -Xms6G
IntCache: cache: 0, tcache: 0, allocated: 13, tallocated: 95
Launched Version: 1.10.1
LWJGL: 2.9.4
OpenGL: ~_ERROR~ RuntimeException: No OpenGL context found in the current thread.
GL Caps: Using GL 1.3 multitexturing.
Using GL 1.3 texture combiners.
Using framebuffer objects because OpenGL 3.0 is supported and separate blending is supported.
Shaders are available because OpenGL 2.1 is supported.
VBOs are available because OpenGL 1.5 is supported.

Using VBOs: Yes
Is Modded: Probably not. Jar signature remains and client brand is untouched.
Type: Client (map_client.txt)
Resource Packs: ChromaHills128x-1.9-v.1.zip
Current Language: English (US)
Profiler Position: N/A (disabled)
CPU: 8x Intel(R) Core(TM) i7-4770K CPU @ 3.50GHz