LexManos

I don't I'm just taking a educated guess. We cant help you more unless you post your logs by trying to run it from the command line and telling us what it says.

You need to use java 8 not java 9. And run it from the command line to get a real error... Also Post useful titles -.-

ya, something you have installed is removing vanilla recipes which breaks the advancements.

How are you running the client? Show screenshots.

There should be more to the logs, showing explciitly what went wrong. However, the vanilla built in advancements are valid syntax so you shouldn't be having this error unless you've changed something. More logs are needed.

The current recommended version is before the library re-write so that doesn't matter. And no the installer will not go around deleting your modlists. That would just be stupid. I've added hardening for broken modlists. That solves this issue, beyond that, you can just delete your json and you'll be fine.

Interesting you are correct that the installer is creating an incorrect json, I wonder when that happened and why it hasn't broken things before now. However, you can just delete the modlist and you'll be fine. I can add hardening for things like this. But doesn't really matter as the modern versions no longer include Mercurius.

"repositoryRoot": "C:/Users/Coolio/AppData/Roaming/.minecraft/server/libraries", Thats your issue that's not a valid repository root. They have always been relative to the MC directory unless you specify "absolute:" before it

Post your mod_list.json files from /mods and /mods/1.12.2/ Seems you've configured it incorrectly.

No, Mods are designed for a specific MC version. Due to things that Mojang does on their end it isn't feasible to make a mod work on multiple versions. You can still play old versions, we just won't help you when it breaks.

You installed Forge which is the issue you originally had, so thats solved. You then mentioned a second crash without following the directions in the EAQ of showing us what the crash was/including your logs. So for all we know you crashes because solar flares excited the electrons in your computer room causing the aurora borealis completely localized in the section of your hard drive that held minecraft.

https://www.digitalcitizen.life/command-prompt-how-use-basic-commands

try using normal command line, instead of powershell. So type cmd And then type the same command.

Remove JujusCoffeeCraft, and tell them to build a real mod. Also update to 1.12.2.

Multicraft is broken then, it should use the installer, or atleast give you the ability to upload all the files the installer generates. 2656+ has a new library dependency, so they need to allow you to install it.

try 2657, and no Umbra, jar mods should not exist anymore... stop talking out of ignorance.

FYI this hasn't been necessary for quite some time. The mojang launcher will download the vanilla version for us.

Advanced Rocketry is a coremod that is breaking things. Stop using it. It's not a Forge issue.

Yes, it was shut down due to progress on the front end not being made. And the server costing way to much to run. It however served its purpose, to some extent. It gave us the stats we needed to know that <J7 was pretty much useless. But then Mojang bumped to J8 in 1.12.2, which means we could as well. So whatever.. But ya it was a experiment, it failed due to many reasons. If you still have it installed it doesn't send any data anywhere so you're good.

Well ya.. I highly doubt your computer has 2TB of ram to dedicate to the server... you seem to of messed up how you're setting the needed ram.

You can always run a specific version of java by using the full path to the java executable.

Eah, still the case if this object is instantiated before the capability is registered. It's still the same problem. As the same issues I specified.

public static final Capability<IMentalTemperature> MentalTemperature_CAP = null; private IMentalTemperature instance = MentalTemperature_CAP.getDefaultInstance(); That code turns into this: public static final Capability<IMentalTemperature> MentalTemperature_CAP; private IMentalTemperature instance; static { MentalTemperature_CAP = null; instance = MentalTemperature_CAP.getDefaultInstance(); } Now, when you see that, isn't the issue OBVIOUS!?! MentalTemprature_CAP WILL ALWAYS BE NULL when you try to call it to set instance. (Also resisting urge to yell at you about code style) @CapabilityHolders are only populated when someone registers a capability. That's the entire freaking point. It's a soft dependency on that class. 1st) You're trying to make a soft dependacy so making a field of that exist type is not recommended. So instance should be Object. 2nd) You should delay creating that instance until it's needed, Or until you are told that that capability exists. You can annotate a method with @CapabilityInject and a single argument of a CapabilityHolder and it'll be called whenever that apropriate cap is registered.

Post your log files, without those we cant tell you why its erroring. You could be doing a million things wrong, you've given us no information to work off of.

Logs, and remove optifine.