The issue might be due to the number of transactions you are trying to import. TurboTax supports Robinhood customers with extensive trading history; however, if you made 1,500 or more equity and options trades in your Robinhood Financial brokerage account or 2,250 or more cryptocurrency trades in your Robinhood Crypto account in the filing year, you may experience difficulty uploading your tax forms directly into TurboTax. You can upload your transaction history by following their instructions. Transactions beyond these limits need to be entered manually.
You can find more information about uploading into TurboTax on the Robinhood website
Dont waste your time. Its total garbage. You'll end up being forced in an infinite death spiral of manual keying dates in that will never resolve in TT because the Robinhood upload is not structured correctly. Worst of all TT is sooo F-ing slow with too many click throughs you'll have to take a day off of work just to sit there and wait for their horrific UI to cycle because they make you page through all your transactions to edit them rather than putting them all on one infinite scrolling page. Its truly one of the worst user experiences and not even worth paying for....but the level of mediocrity makes sense considering the people behind Robinhood.
For me, the csv file did not download/save with the ".csv" file extension.
Find your file, change the name to add the ".csv" at the end and it should work.