Forge not booting at all? Try this...

[CybeastID]

Some people are having an issue where Forge isn't booting, period. There's no log because it's not booting at all. Well... I may have figured out why.

 

Under Minecraft, there is a button labeled edit profile. In there, there is "Use Version". You want to set this to the version that has the word "Forge" in it. If you do not, Minecraft will just boot its vanilla self. And by default, it's on "Use latest version".

 

My point being, if you're having an issue where it doesn't boot Forge, try this and see if Forge loads. If it crashes, well, then you've got other problems, either mod related or forge related, in which case you probably should follow the usual procedure.

[LexManos]

There is a reason why there is a popup at the end of the install that says that it installed to the 'Forge' profile...

Use the Forge profile, else you'll get vanilla.