Are you using the online version of TurboTax for 2016 or the desktop version? You indicated Online Deluxe by your username above and are using the term "upload." And you didn't indicate otherwise when I asked you about Online TurboTax in my first comment above. So I've been assuming you are using the Online version, and that's what this answer addresses.
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Copy the *.tax2015 data file from the flash drive to a folder on your computer such as the \My Documents folder. Then try to upload it from that location.
See the screen images below on how to transfer the *.tax2015 data file into a new 2016 online return. Note that if you already started a 2016 online, return you have to clear it and start over as part of the process.
