Nether portal crash

Please attach the crash report (minecraft/crash-reports/crash-<DATE>-client.txt) here.

When he crashes, he is taken back to the main menu, not the launcher. I don't know if this actually counts as crash or not, but I will see if I can get the log.

Then it's not a crash, but a disconnect, what is the message that your friend gets?

when he takes the portal, his game minimizes, then re-maximizes on its own. It has the normal dirt background, like when you normally take a portal, except the page says not responding. after about 20 seconds, It says "Connection Lost: timed out". When he loads the world back up, he is inside the same wall he was in last time. It seems, through observation, that it only happens when he hasn't been in the nether for a while, or if he goes into the nether from a portal different to the one he came to the over-world from.

Please make your friend force a crash report (F3+C for 10 seconds) and attach it here.

he crashed again, after reloading from the last crash. Funny, he died before he joined the game.

I am TobyCat2, and he is Arial456
full log from launcher up until the point that he disconnected:

Aug 26, 2016 4:37:03 PM net.minecraft.launchwrapper.LogWrapper log
INFO: Loading tweak class name optifine.OptiFineTweaker
Aug 26, 2016 4:37:04 PM net.minecraft.launchwrapper.LogWrapper log
INFO: Using primary tweak class name optifine.OptiFineTweaker
Aug 26, 2016 4:37:04 PM net.minecraft.launchwrapper.LogWrapper log
INFO: Calling tweak class optifine.OptiFineTweaker
OptiFineTweaker: acceptOptions
OptiFineTweaker: injectIntoClassLoader
OptiFine ClassTransformer
OptiFine URL: file:/C:/Users/Luke/AppData/Roaming/.minecraft/libraries/optifine/OptiFine/1.10.2_HD_U_C1/OptiFine-1.10.2_HD_U_C1.jar
OptiFine ZIP file: C:\Users\Luke\AppData\Roaming\.minecraft\libraries\optifine\OptiFine\1.10.2_HD_U_C1\OptiFine-1.10.2_HD_U_C1.jar
OptiFineTweaker: getLaunchArguments
OptiFineTweaker: getLaunchTarget
Aug 26, 2016 4:37:05 PM net.minecraft.launchwrapper.LogWrapper log
INFO: Launching wrapped minecraft {net.minecraft.client.main.Main}
[16:37:06] [Client thread/INFO]: Setting user: Arial456
[OptiFine] (Reflector) Class not present: net.minecraftforge.common.MinecraftForge
[OptiFine] (Reflector) Class not present: net.minecraftforge.common.ForgeHooks
[OptiFine] (Reflector) Class not present: net.minecraftforge.client.MinecraftForgeClient
[OptiFine] (Reflector) Class not present: net.minecraftforge.client.ForgeHooksClient
[OptiFine] (Reflector) Class not present: net.minecraftforge.fml.common.FMLCommonHandler
[OptiFine] (Reflector) Class not present: net.minecraftforge.fml.client.FMLClientHandler
[OptiFine] (Reflector) Method not present: atl.getSkyRenderer
[OptiFine] (Reflector) Method not present: atl.getCloudRenderer
[OptiFine] (Reflector) Method not present: atl.getWeatherRenderer
[OptiFine] (Reflector) Method not present: aid.countEntities
[OptiFine] (Reflector) Method not present: aid.getPerWorldStorage
[OptiFine] (Reflector) Class not present: net.minecraftforge.client.IRenderHandler
[OptiFine] (Reflector) Class not present: net.minecraftforge.common.DimensionManager
[OptiFine] (Reflector) Class not present: net.minecraftforge.event.world.WorldEvent$Load
[OptiFine] (Reflector) Class not present: net.minecraftforge.client.event.RenderItemInFrameEvent
[OptiFine] (Reflector) Class not present: net.minecraftforge.client.event.GuiScreenEvent$DrawScreenEvent$Pre
[OptiFine] (Reflector) Class not present: net.minecraftforge.client.event.GuiScreenEvent$DrawScreenEvent$Post
[OptiFine] (Reflector) Class not present: net.minecraftforge.client.event.EntityViewRenderEvent$FogColors
[OptiFine] (Reflector) Class not present: net.minecraftforge.client.event.EntityViewRenderEvent$RenderFogEvent
[OptiFine] (Reflector) Class not present: net.minecraftforge.client.event.EntityViewRenderEvent$CameraSetup
[OptiFine] (Reflector) Class not present: net.minecraftforge.client.event.RenderLivingEvent$Pre
[OptiFine] (Reflector) Class not present: net.minecraftforge.client.event.RenderLivingEvent$Post
[OptiFine] (Reflector) Class not present: net.minecraftforge.client.event.RenderLivingEvent$Specials$Pre
[OptiFine] (Reflector) Class not present: net.minecraftforge.client.event.RenderLivingEvent$Specials$Post
[OptiFine] (Reflector) Class not present: net.minecraftforge.fml.common.eventhandler.EventBus
[OptiFine] (Reflector) Class not present: net.minecraftforge.fml.common.eventhandler.Event$Result
[OptiFine] (Reflector) Class not present: net.minecraftforge.event.ForgeEventFactory
[OptiFine] (Reflector) Class not present: net.minecraftforge.client.event.RenderBlockOverlayEvent$OverlayType
[OptiFine] (Reflector) Class not present: net.minecraftforge.event.world.ChunkWatchEvent$UnWatch
[OptiFine] (Reflector) Method not present: akf.getBedDirection
[OptiFine] (Reflector) Method not present: akf.isBed
[OptiFine] (Reflector) Method not present: akf.isBedFoot
[OptiFine] (Reflector) Method not present: akf.hasTileEntity
[OptiFine] (Reflector) Method not present: akf.canCreatureSpawn
[OptiFine] (Reflector) Method not present: akf.addHitEffects
[OptiFine] (Reflector) Method not present: akf.addDestroyEffects
[OptiFine] (Reflector) Method not present: akf.isAir
[OptiFine] (Reflector) Method not present: akf.canRenderInLayer
[OptiFine] (Reflector) Method not present: akf.getExtendedState
[OptiFine] (Reflector) Field not present: rw.captureDrops
[OptiFine] (Reflector) Field not present: rw.capturedDrops
[OptiFine] (Reflector) Method not present: rw.shouldRenderInPass
[OptiFine] (Reflector) Method not present: rw.canRiderInteract
[OptiFine] (Reflector) Method not present: rw.shouldRiderSit
[OptiFine] (Reflector) Method not present: aqk.shouldRenderInPass
[OptiFine] (Reflector) Method not present: aqk.getRenderBoundingBox
[OptiFine] (Reflector) Method not present: aqk.canRenderBreaking
[OptiFine] (Reflector) Method not present: adx.onEntitySwing
[OptiFine] (Reflector) Method not present: adx.shouldCauseReequipAnimation
[OptiFine] (Reflector) Method not present: adx.showDurabilityBar
[OptiFine] (Reflector) Method not present: adx.getDurabilityForDisplay
[OptiFine] (Reflector) Method not present: rp.shouldRenderHUD
[OptiFine] (Reflector) Method not present: rp.renderHUDEffect
[OptiFine] (Reflector) Method not present: rq.isCurativeItem
[OptiFine] (Reflector) Method not present: aeo.getRecordResource
[OptiFine] (Reflector) Method not present: bwp$b.preDraw
[OptiFine] (Reflector) Method not present: bwp$b.postDraw
[OptiFine] (Reflector) Class not present: net.minecraftforge.fml.common.asm.transformers.BlamingTransformer
[OptiFine] (Reflector) Class not present: net.minecraftforge.fml.relauncher.CoreModManager
[OptiFine] (Reflector) Class not present: net.minecraftforge.fml.client.SplashProgress
[OptiFine] (Reflector) Class not present: net.minecraftforge.client.model.pipeline.LightUtil
[OptiFine] (Reflector) Class not present: net.minecraftforge.common.property.IExtendedBlockState
[OptiFine] (Reflector) Class not present: net.minecraftforge.client.ItemModelMesherForge
[OptiFine] (Reflector) Class not present: net.minecraftforge.client.model.ModelLoader
[OptiFine] (Reflector) Class not present: net.minecraftforge.client.model.Attributes
[OptiFine] (Reflector) Class not present: mods.betterfoliage.client.BetterFoliageClient
[OptiFine] (Reflector) Method not present: aiq.getWaterColorMultiplier
[OptiFine] (Reflector) Class not present: net.minecraftforge.fml.client.registry.RenderingRegistry
[OptiFine] (Reflector) Method not present: bqf.preDrawBatch
[OptiFine] (Reflector) Method not present: bqf.drawBatch
[OptiFine] (Reflector) Method not present: bpj.handleItemState
[OptiFine] (Reflector) Class not present: net.minecraftforge.common.ForgeModContainer
[OptiFine] (Reflector) Class not present: net.minecraftforge.client.settings.KeyConflictContext
[OptiFine] (Reflector) Method not present: bcu.setKeyConflictContext
[OptiFine] (Reflector) Method not present: bcu.setKeyModifierAndCode
[OptiFine] (Reflector) Method not present: bcu.getKeyModifier
[OptiFine] (Reflector) Class not present: net.minecraftforge.client.settings.KeyModifier
[16:37:10] [Client thread/INFO]: LWJGL Version: 2.9.4
[OptiFine] 
[OptiFine] OptiFine_1.10.2_HD_U_C1
[OptiFine] Build: 20160629-180519
[OptiFine] OS: Windows 7 (x86) version 6.1
[OptiFine] Java: 1.7.0_21, Oracle Corporation
[OptiFine] VM: Java HotSpot(TM) Client VM (mixed mode), Oracle Corporation
[OptiFine] LWJGL: 2.9.4
[OptiFine] OpenGL: Intel 945GM, version 1.4.0 - Build 8.14.10.1930, Intel
[OptiFine] OpenGL Version: 1.4
[OptiFine] OpenGL Fancy fog: Not available (GL_NV_fog_distance)
[OptiFine] OpenGL Occlussion culling: Not available (GL_ARB_occlusion_query)
[OptiFine] Maximum texture size: 2048x2048
[Shaders] ShadersMod version: 2.4.12
[Shaders] OpenGL Version: 1.4.0 - Build 8.14.10.1930
[Shaders] Vendor:  Intel
[Shaders] Renderer: Intel 945GM
[Shaders] Capabilities:  -  -  -  -  - 
[Shaders] GL_MAX_DRAW_BUFFERS: 7
[Shaders] GL_MAX_COLOR_ATTACHMENTS_EXT: 7
[Shaders] GL_MAX_TEXTURE_IMAGE_UNITS: 16
[Shaders] Load ShadersMod configuration.
[Shaders] Save ShadersMod configuration.
[Shaders] Shaders can not be loaded, Fast Render is enabled.
[Shaders] No shaderpack loaded.
[OptiFine] Checking for new version
[OptiFine] Version found: C1
[16:37:16] [Client thread/INFO]: Reloading ResourceManager: Default
[OptiFine] *** Reloading textures ***
[OptiFine] Resource packs: Default
[16:37:17] [Sound Library Loader/INFO]: Starting up SoundSystem...
[16:37:18] [Thread-6/INFO]: Initializing LWJGL OpenAL
[16:37:18] [Thread-6/INFO]: (The LWJGL binding of OpenAL.  For more information, see http://www.lwjgl.org)
[OptiFine] Multitexture: false
[OptiFine] BetterGrass: Parsing default configuration optifine/bettergrass.properties
[16:37:20] [Client thread/INFO]: Created: 512x512 textures-atlas
[OptiFine] *** Reloading custom textures ***
[16:37:27] [Thread-6/INFO]: OpenAL initialized.
[16:37:27] [Sound Library Loader/INFO]: Sound engine started
[16:38:02] [Client thread/INFO]: Realms library version == 1.9.5
[16:38:02] [MCO Compatability Checker #1/INFO]: Realms is available for this user
[16:38:02] [Client thread/ERROR]: ########## GL ERROR ##########
[16:38:02] [Client thread/ERROR]: @ Post render
[16:38:02] [Client thread/ERROR]: 1281: Invalid value
[16:38:03] [Client thread/ERROR]: ########## GL ERROR ##########
[16:38:03] [Client thread/ERROR]: @ Post render
[16:38:03] [Client thread/ERROR]: 1281: Invalid value
[16:42:18] [Client thread/INFO]: [CHAT] Arial456 has just earned the achievement [Return to Sender]
[16:43:05] [Client thread/ERROR]: Item entity 1088 has no item?!
[17:01:28] [Client thread/INFO]: [CHAT] You can only sleep at night
[17:05:47] [Client thread/INFO]: [CHAT] TobyCat2 joined the game
[17:06:02] [Client thread/ERROR]: Item entity 23784 has no item?!
[17:06:02] [Client thread/ERROR]: Item entity 23784 has no item?!
[17:06:02] [Client thread/ERROR]: Item entity 23784 has no item?!
[17:06:02] [Client thread/ERROR]: Item entity 23784 has no item?!
[17:07:47] [Client thread/INFO]: [CHAT] TobyCat2 left the game
[17:08:03] [Client thread/INFO]: [CHAT] TobyCat2 joined the game
[17:09:28] [Client thread/INFO]: [CHAT] <TobyCat2> ZZtoop
[17:09:34] [Client thread/INFO]: [CHAT] <Arial456> sdkfhasdfghae;rrjfghcaoeurhgauaerhgujaerhgaewrh;oairwe
[17:10:29] [Client thread/ERROR]: Item entity 37645 has no item?!
[17:10:29] [Client thread/ERROR]: Item entity 37645 has no item?!
[17:10:29] [Client thread/ERROR]: Item entity 37645 has no item?!
[17:12:16] [Client thread/INFO]: [CHAT] TobyCat2 left the game
[17:12:30] [Client thread/INFO]: [CHAT] TobyCat2 joined the game
[17:13:32] [Client thread/INFO]: [CHAT] TobyCat2 left the game
[17:13:48] [Client thread/INFO]: [CHAT] TobyCat2 joined the game
[17:14:16] [Client thread/INFO]: [CHAT] TobyCat2 left the game
[17:14:38] [Client thread/INFO]: [CHAT] TobyCat2 joined the game
[17:15:49] [Client thread/INFO]: [CHAT] TobyCat2 left the game
[17:16:03] [Client thread/INFO]: [CHAT] TobyCat2 joined the game
[17:16:41] [Client thread/INFO]: [CHAT] TobyCat2 left the game
[17:17:06] [Client thread/INFO]: [CHAT] TobyCat2 joined the game
[17:33:31] [Client thread/ERROR]: Item entity 100026 has no item?!
[17:33:33] [Client thread/ERROR]: Item entity 100026 has no item?!
[17:33:33] [Client thread/ERROR]: Item entity 100026 has no item?!

This site is for addressing issues related to the base unmodded Minecraft; Bukkit, Spigot, Forge, Optifine, or any other modded system invalidates your ticket.

[16:38:03] [Client thread/ERROR]: ########## GL ERROR ##########
[16:38:03] [Client thread/ERROR]: @ Post render
[16:38:03] [Client thread/ERROR]: 1281: Invalid value

Also, dupe of MC-297

I am having the same problem, I even exported my worlds, uninstalled the game, reinstalled the game, and imported my worlds back in, and it still doesn't let me go through my nether portal into the overworld without my game crashing. PLEASE FIX!