Crash on first launch involving "Sending event FMLConstructionEvent to mod hammercore"

Have tried to launch the modpack for several versions now, and have gotten consistent timeouts during the initial load of the pack. Multiple versions of java have been used, including 1.8.0_401 and 1.8.0_349. This line has appeared on every crash log to date as the final line prior to the timeout.

To Reproduce

Steps to reproduce the behavior:

1. Download pack
2. Install either with or without Optifine
3. Launch pack
4. Timeout at HammerLib construction

Modpack version v1.30.0

Screenshot

Debug Log

End of Minecraft Log through Prism

Separate crash on startup
(happened twice when trying to suss out the problem)
https://mclo.gs/uZCDYnx

Hoping to learn what the error is so that I can play the pack properly, have been looking forward to it since I saw the pack on CurseForge about a month ago. Unfortunately, this error has plagued me the entire time, no matter what java or driver updates I use. Thanks!

Regarding this error, I have received report from players in my modpack a long time ago, but it is very rare, but you can try downgrading the HammerCore/HammerLib mod to this version(There is no guarantee that the problem will be solved, and I didn't find anything in the mod's change log that might cause the problem)

I just encountered same crash NoClassDefFoundError: net/minecraftforge/client/model/pipeline/VertexLighterFlat on mentioned version.

So I could only make assumption that HammerLib is not the reason or HammerLib version downgrade actually wont matter.
Log for history: https://mclo.gs/erRtL3i.

So, my other assumption that downgrading changing mod count / mod versions that causing re-creating of cache of some other mod, thus clearing erroring code.

I think, if @danereinsch will install HammerLib-1.12.2-12.2.48 back his game will still load.

The error itself happens randomly and fixed by changing mod count / mod versions.

Since I cannot reproduce this issue and no players reported this issue last months, probably its happens very rare or fixed by mod updates. Also, looking to Discord history, 5 months ago some players fixed this issue by just restarting game.

So, i think i could close the issue. If someone will have this crash again, feel free to write here.

Reopen issue since new player reported same issue today https://mclo.gs/4lW4Dtf

Thank you for the report!

I will investigate issue further.

Please send logs/debug.log file. You may need to enable generation of this file in your MC instance settings.

Regarding this error, I have received report from players in my modpack a long time ago, but it is very rare, but you can try downgrading the HammerCore/HammerLib mod to this version(There is no guarantee that the problem will be solved, and I didn't find anything in the mod's change log that might cause the problem)

Regarding this error, I have received report from players in my modpack a long time ago, but it is very rare, but you can try downgrading the HammerCore/HammerLib mod to this version(There is no guarantee that the problem will be solved, and I didn't find anything in the mod's change log that might cause the problem)

Thanks for the hint!

The issue could be also related to this config option:

The issue could be also related to this config option:

Alright so I've attempted to start the pack again with the suggested change, and now I'm getting this crash on load consistently: https://mclo.gs/kpvDCXQ . It appears to be related to VertexLighterFlat, but I'm unsure.

Alright so I've attempted to start the pack again with the suggested change, and now I'm getting this crash on load consistently: mclo.gs/kpvDCXQ . It appears to be related to VertexLighterFlat, but I'm unsure.

Please double-check if you have mod duplicates in your mods/ folder. It could be one of those mods:

ActuallyBaubles-1.12-1.1
architecturecraft-1.12-3.108
Avaritia-1.12.2-3.3.0.37-universal
Bedrock Ores-MC1.12-1.2.7.42
betteranimalsplusplus-4-13-2022b
BiomesOPlenty-1.12.2-7.0.1.2445-universal
Botania r1.10-364.4
botaniatweaks-1.9.1
cc-tweaked-1.12.2-1.89.2
ColossalChests-1.12.2-1.7.3
EnderIO-1.12.2-5.3.72
EndReborn [0.3.9]
ExCompressum_1.12.2-3.0.32
exnihilocreatio-1.12.2-0.4.7.2
forestry_1.12.2-5.8.2.422
iceandfire-1.9.1-1.12.2
ImmersiveCables-1.12.2-1.3.2
ImmersiveEngineering-0.12-98
industrialcraft-2-2.8.222-ex112
IntegratedCrafting-1.12.2-1.0.10
IntegratedDynamics-1.12.2-1.1.11
IntegratedTerminals-1.12.2-1.0.14
IntegratedTunnels-1.12.2-1.6.14
JustEnoughResources-1.12.2-0.9.2.60
LibVulpes-1.12.2-0.4.2-25-universal
MCTSmelteryIO-1.12.2-1.2.63
Mekanism-Community-Edition-1.12.2-9.12.8-Core
mia-1.12.2-0.2.2a
oeintegration-2.3.4
OldJavaWarning-1.12.2-1.1.11
OpenComputers-MC1.12.2-1.8.3+274990f
OpenTerrainGenerator-1.12.2-v9.5-R1
plethora-1.12.2-1.2.3
QuarkRotN-r1.6-188
RandomThings-MC1.12.2-4.2.7.4
rats-3.2.21-1.12.2
Requious Frakto-0.12
rustic-1.1.7
ScalingHealth-1.12.2-1.3.42+147
TConstruct-1.12.2-2.13.0.183
Thaumcraft-1.12.2-6.1.BETA26
thaumicwonders-1.8.2
thaumtweaks-0.3.5.3
ThermalDynamics-1.12.2-2.5.6.1-universal
ThermalExpansion-1.12.2-5.5.7.1-universal
ThermalInnovation-1.12.2-0.3.6.1-universal
TravelersBackpack-1.12.2-1.0.35
twilightforest-1.12.2-3.11.1021-universal
twilighttweaks-1.12.2-v1.0.2.jar
voidislandcontrol-1.5.3
xnet-1.12-1.8.2

UPDATE:
I've swapped out the included version of HammerCore/HammerLib to the one recommended by @mczph and it seems to work now! Thanks for the help y'all. Not sure why the updated file seems to not work properly, but I'm also not exactly an expert in this area. Additionally, I did not find any duplicated files in the mods folder, so I do not believe that was the cause. I feel pretty comfortable in saying that the HammerCore version or an interaction between it and (maybe) ArmoryExpansion or a different mod caused the crashes on startup.

Regarding this error, I have received report from players in my modpack a long time ago, but it is very rare, but you can try downgrading the HammerCore/HammerLib mod to this version(There is no guarantee that the problem will be solved, and I didn't find anything in the mod's change log that might cause the problem)

Good. I will consider to downgrade HammerCore then.

Really a strange problem. It seems to only occur in a small part of PC environments.

Update:
Seems like SledgeHammer wasnt the reason because today i found a player who had error NoClassDefFoundError: VertexLighterFlat without SledgeHammer https://mclo.gs/TH8yjpr

Should be fixed in next modpack version through this commit dragon-forge/HammerLib@aeb705e

Should be fixed in https://github.com/Krutoy242/Enigmatica2Expert-Extended/releases/tag/v1.43.0