The Business Edition has nothing at all to do with the Online TurboTax website, which is only for personal tax returns.
"when I try to find my turbotax business 2015 file online"
Your 2015 business tax file will not be in an Online account. The Business Edition is a desktop-only product and all data files are stored locally on your computer. Search your entire computer system and any backup external media for the *.tax2015 data file. It is not in an Online account.
