I've tried, for days. It will open the tab, it'll say Forge, it'll be loading and loading, and then it will go back in to the launcher and say, "You are using an unsupported modified version of the game." I saw an old post saying you needed ModLoader in addition to Forge, but I tried to find, "Modloader", And all I can find is links to download forge. I'm probably missing something, but if anyone could could clear my confusion I would be very thankful.
Modloader is incredibly out of date. Forge is a standalone modloader that doesn't require anything else. Download the Forge 1.12.2 installer from their official website (here's the link to it) and run it. It'll install everything it needs to run Minecraft Forge for 1.12.2. If it crashes, post the full crashlog using a website like paste.ubuntu.com.
I believe that fixed the initial problem, but now the forge loading screen will show, and before it can load, it will say "An unexpected issue occurred and the game has crashed. We're sorry for the inconvenience." That only ever shows up if I allocate more RAM to the profile. If I don't allocate more it will just be so slow that the world never loads, it says my laptop has over 6 GB of available RAM. Am I doing something else wrong? Should I post the crashlog still?
Say something silly, Laugh 'til it hurts, Take a risk, Sing out loud, Rock the boat, Shake things up, Flirt with disaster, Buy something frivolous, Color outside the lines, Cause a scene, Order dessert, Make waves, Get carried away, Have a great day!
I am so sorry! But I think I just figured it out. When I pasted it I could actually read it and I figured it out. I was just allocating a bit too much and it was crashing, but I found a sweet spot and it seems to be working perfectly. Thanks for the help! Sorry for wasting more of your time!