Just installed an FSA compact crankset, and when the chain is in the front 34 ring, and rear 12 cog there is a very slight rubbing of the chain against the inside of the 50 ring. I have adjusted everything possible, and can't get rid of it. I am using a Shimano HG chain. Should I try a different chain, or just learn to live with it? Any ideas?

Maybe if you put a spacer under your drive side BB it will reduce the angle enough to eliminate the rub. You will have to watch for clearance between your left crank and chainstay. Otherwise you will need a wider BB.

I could try a BB for a triple, but I don't think the drivetrain will line up correctly. I have been looking around the web, and it seems to be a common issue, and many people had said that you are not supposed to use the smallest rear cog while in the 34 ring.

Normal, mine does the same on the 2 smallest cogs on the cassette. Just don't use those as you should be on the big ring before then anyway.

Just stay out of the small cogs when in the 34! A narrower chain could work but is not the correct solution.. It even happens on many bikes with 39/53 rings depending on chainstay length.and chainline.

They are RIGHT!