Yes, I have tried twice this year with two different client TTO data files and have had the same error message.  To provide some background, I did request they send the .tax2019 files via a shared Dropbox folder I set up for us to use.  They found the data file in TTO and uploaded it to Dropbox.  I figured I was good to go...just perform the transfer TT data file to 2019 proseries.  Not so fast.  Same error you got.  I looked back and noticed the .tax2019 file when I download it from Dropbox shows as a .pdf file.  I am stumped by this.  This procedure has gone off without a hitch in past years, but for some reason the 2019 TTO data files are not cooperating. Intuit needs to escalate this.  Getting that file saves a lot of time, especially if the new client has a lot of carryover info like depreciation schedules, or PAL or at-risk losses,