Can you return the CD after you've already downloaded the product if you can't convert to the online version?
That is a question to ask Costco. Costco has your money. TurboTax does not.
Did the same exact thing. Would think that would be simple given its 2020.
The CD/download product and the Online products are very different with different fees, different structure, and different included features. Many of the online products have form limitations that require higher editions. The desktop editions do not have such form limitations. And most of the desktop editions include a state program (Desktop Basic does not have a state program, and desktop Deluxe comes both ways--with or without a state program included.)
Also, the Online version can only prepare 1 Federal return per account. The desktop version can prepare multiple Federal returns with up to 5 Federal efiles. In the desktop version there is a 19.99 fee to efile a state return (24.99 later in filing season), but no state efile fee for a New York state return, and no fee to print and mail the state returns.
Also, the desktop version has the advantage of having Forms View, which online products do not have. This can be a valuable tool for troubleshooting and correcting a form.
If you bought the CD or download and want to use Online TurboTax instead, if Costco will not refund your purchase, you can use this online Refund Request tool. TurboTax desktop software has a 60-day satisfaction guarantee.
https://support.turbotax.intuit.com/forms/refund-request.jsp
I added an additional paragraph to my answer above showing some additional contrasts between online and desktop products. You may have been emailed the original before the addition. If so, please return to the forum to see the full info.