DaemonUmbra

The task is setupDecompWorkspace, not just decompWorkspace

I'm getting off track with this, do you have the installer log? The one that the Forge installer creates.

Do you have a logs folder in your .minecraft folder? I am not asking for the launcher log, I am asking for debug.log or latest.log Ok so it doesn't even get to the point where the client takes over... I get it now

This is all moot, Forge for 1.13 isn't out yet. For the record, to my knowledge the error that the Minecraft Client can't download the Forge jar is intentional, the Forge jar should only come from the Forge installer.

You are trying to run 1.12.2 Techguns on Minecraft 1.12.1 Given that you are new to modded minecraft I would like you to take a look at the thread I've linked here, both me and another mod gave our comments to another person new to the world of modded minecraft.

Can you post the installer log?

It might be cfm.cfg, since the undescriptive "cfm" is unfortunately what he uses as the Mod ID.

Do not use 9Minecraft for Mods, see the StopModReposts project to learn why.

MrCrayfish's Furniture mod is trying to use Client-Only code on the server side. This has been fixed on the GitHub but hasn't been fixed in a release yet, I believe the workaround is to disable the welcome message in the mod's config file.

What steps did you follow setting up the mods for this instance, go through what installers you used, the order you used them in, and the options you chose in each one.

Remove NotEnoughIDs, according to Lex this mod has been confirmed to muck up network handshakes, which is what is happening here.

Do you have the installer log?

Can I just have you confirm where you are getting Forge from? The specific URL please.

Did you delete Forge from your versions folder before re-running the installer?

Can you give the URL for "the forge website"? and I mean a URL to the download page, not "this site".

debug.log should be in your logs folder, as described in my signature.

1.7.10 is no longer supported on the forums due to its age. Please update to a Modern version of Minecraft to receive support.

What launcher are you using?

To make a Gist yes you will have to, but unless you need access to extra features on GitHub it won't cost you a thing.

Please post the full log as described in my signature.

Can you please post your full log as described in my signature?

It looks like the JSON file storing your island locations was corrupted

This looks like the same problem you had in this thread. Why did you make a new thread?

Then you need to re-run the Forge installer, if the issue persists you may need to delete that version of Forge from your versions folder and re-re-run the installer.

Forge has had a built-in Chunk Generation command since the end of last year by the way. The auto restart is coming from the chunk pre-generator mod and is an option in the mod's config file. If I may put a personal note here, I'm not overly fond of mods that log their stuff to the FML logger, putting the FML name to their own log messages and hiding the true source of the message.