I've been having this issue whenever I try to create a new 1.12.2 world in modded minecraft (Forge). Vanilla works absolutely fine, the mods I use work fine in 1.7.10 (some of the 1.12.2 versions have new dependent mods with them, but still load in forge). I piece together mods instead of using a modpack because I have yet to find one that has the mods I want, and none that I don't. Minecraft will load through the mods fine, I can get to the singleplayer/multiplayer selection screen just fine. I can get to the world creation just fine and set it up, but as it starts to actually load and build the world, it takes about 15 minutes to do anything, then will pop up "internal exception: java.nio.channels.closedchannelexception". I'll click the "return to server list" button and it sends me to the multiplayer menu (nothing loads as I'm not on any). I honestly have no clue what could be causing this. I have no idea about mod tweeking, but since they load fine before I create a new world, I don't think it would be the mods, but I may be wrong.
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That's the thing, there is no crash report. It's not actually "crashing", just giving that error on the loading screen and that's it. I click to "return to server list" and then it sits there trying to load multiplayer, even though I wasn't trying to access multiplayer, only singleplayer.
Again, there is no crash log whatsoever. If there's a difference between that and an output log, I have no clue. I've never had any problems until now, so am very ignorant with all these things. I've taken all the mods out and tried putting them back in 1 at a time with the same result even on adding just the first mod (and have tried using different mods first). My computer has been shut off and turned back on several times, still with the same result. I won't be able to reply for a couple days as I'll be away, but when I get back, I'll take screen shots of what I'm getting, and if possible some sort of report.
In the folder you have your modded install, there should be a folder called "logs", in that should be your client log files. These are usually pretty large depending on the amount of mods you are running. Though if the client won't create a world, then it might not be too large. Anyway, see if there's a file called "fml-client-latest.log" or just "latest.log", there could be both. If they aren't too large, open them in Notepad++ (any other text editor might have issues with large text files) and copy the contents and put it into paste.ubuntu.com and post the link here. If the log files are large, as in over 5 MB, then just zip it and upload it to a file sharing site and post the link. There might be some useful information in there, hopefully.
I've been having this issue whenever I try to create a new 1.12.2 world in modded minecraft (Forge). Vanilla works absolutely fine, the mods I use work fine in 1.7.10 (some of the 1.12.2 versions have new dependent mods with them, but still load in forge). I piece together mods instead of using a modpack because I have yet to find one that has the mods I want, and none that I don't. Minecraft will load through the mods fine, I can get to the singleplayer/multiplayer selection screen just fine. I can get to the world creation just fine and set it up, but as it starts to actually load and build the world, it takes about 15 minutes to do anything, then will pop up "internal exception: java.nio.channels.closedchannelexception". I'll click the "return to server list" button and it sends me to the multiplayer menu (nothing loads as I'm not on any). I honestly have no clue what could be causing this. I have no idea about mod tweeking, but since they load fine before I create a new world, I don't think it would be the mods, but I may be wrong.
The mods I have are:
Voxel Maps
Mo Villages
Backpacks
Baubles
Bibliocraft
Biomes O Plenty
Botania
Chisel
CodeChicken Lib
CTM-MC
Decocraft
Dense Metals
Drzhark's Mo Creatures
ExtraUtilities2
MrCrayfish's Furniture
HWYLA
Ichunutil
Inventory Pets
Iron Chests
JEI
Malasis Core
Malasis Doors
Mantle
Minecraft Comes Alive
Orespawn
Pam's Harvest Craft
Portalgun
Radixcore
Tinkers Construct
Treecapitator
Post the crash report. Use https://paste.ubuntu.com/
That's the thing, there is no crash report. It's not actually "crashing", just giving that error on the loading screen and that's it. I click to "return to server list" and then it sits there trying to load multiplayer, even though I wasn't trying to access multiplayer, only singleplayer.
Did you try turning it off and on again? Sorry but without any kind of info all we can do is guess. Provide crash report / game output / logs.
Again, there is no crash log whatsoever. If there's a difference between that and an output log, I have no clue. I've never had any problems until now, so am very ignorant with all these things. I've taken all the mods out and tried putting them back in 1 at a time with the same result even on adding just the first mod (and have tried using different mods first). My computer has been shut off and turned back on several times, still with the same result. I won't be able to reply for a couple days as I'll be away, but when I get back, I'll take screen shots of what I'm getting, and if possible some sort of report.
In the folder you have your modded install, there should be a folder called "logs", in that should be your client log files. These are usually pretty large depending on the amount of mods you are running. Though if the client won't create a world, then it might not be too large. Anyway, see if there's a file called "fml-client-latest.log" or just "latest.log", there could be both. If they aren't too large, open them in Notepad++ (any other text editor might have issues with large text files) and copy the contents and put it into paste.ubuntu.com and post the link here. If the log files are large, as in over 5 MB, then just zip it and upload it to a file sharing site and post the link. There might be some useful information in there, hopefully.
Here's a link to Notepad++, it's free https://notepad-plus-plus.org/
D_B
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