Me and my brother have been trying to play Minecraft LAN with mods for the last few days. We have done it successfully before, but now it won't work and we don't know why. When I open a world to LAN, it won't show up in the multiplayer menu on my brother's computer. When he opens a world to LAN, it shows up on mine, and when I go to join it says "Logging In..." then it says "Failed To Connect - Fatally Missing Blocks and Items". When I saw this, we both thought that maybe one of our mods was the wrong version or one of us had a mod the other didn't or something along that line. After going through our files, we have the exact same mods. We also tried deleting the config files then letting them regenerate, and again, we got the same error. The day before this started, we had opened a world in 1.8.1 without mods to test to see if we could connect, because this has happened a few times before, and it worked. But after switching to 1.7.10 and adding mods, it didn't work. Then we switched back to 1.8.1 without mods, and it still didn't work. We have both played in our own worlds with the same set of mods and everything worked fine, but when we try to connect to the others world, it doesn't work.
On one occasion previously to this one, the same thing happened (except the fatally missing blocks and items part) and my brother went into his control panel and found a checkbox that prevented him from allowing others to connect to his computer. But that is no longer an issue. Other times when this has happened, we always just gave up and played a different game then checked back in a month or so.
I would suggest writing down all the mods you have and downloading them again all from the same websites. Some websites say "we have version: (insert version here) and even when you download the file it will say the version you are looking for yet its not which would cause a version conflict. Another thing could be that the forge versions are different. Make sure you have the exact same forge versions. Last tip: when you download the mods download them on one computer and then copy them onto an external storage device, then plug it in to the other computer and use them. This will solve the problems of what I said before about websites false advertising. You will DEFINITELY 100% (hopefully!) have the exact same mods.
IF THAT DIDN'T WORK:
OH AND ALSO!: These are mods!!!! Some mods JUST DO NOT play well with each other in certain scenarios. This process might be tedious but if what I suggested before doesn't work then try this: what you could do is put one mod in, run MC, do the LAN thing, see if it works, if so then that mod is good! If not then try another. Same result? Then I really have no idea. BUT! If it does work then you know a mod is not liking something!!!! You need to repeat this process with every mod. THIS IS IMPORTANT!!!l: If a mod works with a LAN world then keep it in your mods folder and do not remove because that means the mod is working ok! Now you need to add one more mod and repeat the process of relaunching MC, making a LAN world and seeing if it works! Do this process over and over again until you find that your problem appears again. After this discard that mod that you last put in because it is part of the problem.
I AM HORRIBLE AT EXPLAINING THINGS! SORRY IF YOU ARE TOTALLY LOST ON WHAT TO DO!!!
So, if none of this works then I have no idea. I am far from a modder but I do know really well how to troubleshoot, so this is what I can suggest. Hope I this helps!
Me and my brother have been trying to play Minecraft LAN with mods for the last few days. We have done it successfully before, but now it won't work and we don't know why. When I open a world to LAN, it won't show up in the multiplayer menu on my brother's computer. When he opens a world to LAN, it shows up on mine, and when I go to join it says "Logging In..." then it says "Failed To Connect - Fatally Missing Blocks and Items". When I saw this, we both thought that maybe one of our mods was the wrong version or one of us had a mod the other didn't or something along that line. After going through our files, we have the exact same mods. We also tried deleting the config files then letting them regenerate, and again, we got the same error. The day before this started, we had opened a world in 1.8.1 without mods to test to see if we could connect, because this has happened a few times before, and it worked. But after switching to 1.7.10 and adding mods, it didn't work. Then we switched back to 1.8.1 without mods, and it still didn't work. We have both played in our own worlds with the same set of mods and everything worked fine, but when we try to connect to the others world, it doesn't work.
On one occasion previously to this one, the same thing happened (except the fatally missing blocks and items part) and my brother went into his control panel and found a checkbox that prevented him from allowing others to connect to his computer. But that is no longer an issue. Other times when this has happened, we always just gave up and played a different game then checked back in a month or so.
Suggestions?
Mod List:
SecurityCraft
ArmorStatusHUD
Chimneys
DirectionHUD
StatusEffectHUD
Lucky Blocks
Armourers Workshop
AsieLib
AutoSwitch
BiblioCraft
Carpenter's Blocks
Chisel
CodeChickenCore
CoFHCore
CraftGuide
CraftHeraldry
Custom Selection Box
Dynamic Transport
Extra Farming
FastCraft
Flans Mod
FpsPlus
Fun World Generator
Gravity Gun
Headcrumbs
iChunUtil
JBRobot Model
JointBlock
MalisisCore
MalisisDoors
Mantle
More Pistons
Mr Crayfish Furniture
Optifine
Old World Generator
PlanetguyLib
Portal Gun
Randomite
RopePlus
Real World Generator
Slimevoid Library
Starminer
Statues
TConstruct
TheBombzenAPI
TiCTooltops
TLSpecialArmor
TMechworks
TooManyItems
TorchLevers
Warstuff
WirelessRedstoneCore
I would suggest writing down all the mods you have and downloading them again all from the same websites. Some websites say "we have version: (insert version here) and even when you download the file it will say the version you are looking for yet its not which would cause a version conflict. Another thing could be that the forge versions are different. Make sure you have the exact same forge versions. Last tip: when you download the mods download them on one computer and then copy them onto an external storage device, then plug it in to the other computer and use them. This will solve the problems of what I said before about websites false advertising. You will DEFINITELY 100% (hopefully!) have the exact same mods.
IF THAT DIDN'T WORK:
OH AND ALSO!: These are mods!!!! Some mods JUST DO NOT play well with each other in certain scenarios. This process might be tedious but if what I suggested before doesn't work then try this: what you could do is put one mod in, run MC, do the LAN thing, see if it works, if so then that mod is good! If not then try another. Same result? Then I really have no idea. BUT! If it does work then you know a mod is not liking something!!!! You need to repeat this process with every mod. THIS IS IMPORTANT!!!l: If a mod works with a LAN world then keep it in your mods folder and do not remove because that means the mod is working ok! Now you need to add one more mod and repeat the process of relaunching MC, making a LAN world and seeing if it works! Do this process over and over again until you find that your problem appears again. After this discard that mod that you last put in because it is part of the problem.
I AM HORRIBLE AT EXPLAINING THINGS! SORRY IF YOU ARE TOTALLY LOST ON WHAT TO DO!!!
So, if none of this works then I have no idea. I am far from a modder but I do know really well how to troubleshoot, so this is what I can suggest. Hope I this helps!
Thanks! When we get the chance we will try it!