Using TurboTax Business 2019, I am not able to convert a 2018 Business return to 2019.

[VolvoGirl]

They are both the Windows Turbo Tax Business programs?  You can't transfer between Home & Business and Business.  And you are transferring the file ending in .tax2018?  See if you have any other .tax2018 files on your computer.  Both the Business returns and Personal returns end in the same .tax2018.

[gbomalley]

I have two Business returns prepared in TurboTax Business 2018 (not home and business).  One of the returns converted to TurboTax Business 2019, but the second return will not convert.  Yes, they both have the same file type extensions on them.  In 15 years as a user, I have never had a file not convert to the next year.