10.11 finder won't burn bd-r

I recently bought a Mac Pro 4 1 that included a Bluray writer, lg WH12LS38. Everything online says i can burn bluray data in finder but I can't seem to get it to work. Finder seems to recognize the disc and the sys profiler says that i am capable of burning bd-r but the disc shows up as Zero Capacity. I'd really like to archive my old work files and they just won't fit on DVD.

Any ideas? Preferably not the shell out money for Toast. Do the even still make Toast?

thanks