To transfer an Online return to Desktop Mac program see this
https://ttlc.intuit.com/questions/1901265-transfer-last-year-s-return-into-turbotax-for-mac
And scroll down to the last section Transfer your Online Return
You can try to get your tax file here
https://ttlc.intuit.com/questions/3371455-how-do-i-get-a-copy-of-the-2015-return-i-filed-in-turbotax-online
Or You can try to get your tax file by using the How to amend steps. Just use steps 1-4.
To transfer an Online return to Desktop Mac program see this
https://ttlc.intuit.com/questions/1901265-transfer-last-year-s-return-into-turbotax-for-mac
And scroll down to the last section Transfer your Online Return
You can try to get your tax file here
https://ttlc.intuit.com/questions/3371455-how-do-i-get-a-copy-of-the-2015-return-i-filed-in-turbotax-online
Or You can try to get your tax file by using the How to amend steps. Just use steps 1-4.
If you have a copy of your 2016 Online return in .tax2016 data file format, just follow the first set of instructions above.
If you don't, use this workaround:
Now, open the .tax2017 file (which contains the transferred 2016 info) in TurboTax for Windows:
https://ttlc.intuit.com/replies/3302290