Which product did you buy at Costco, the Online version, or the CD/Download version? 21 character Installation keys are only used for TurboTax CD/Download. TurboTax Online uses 11 character prepayment codes. The codes from TurboTax CD/Download will not work with TurboTax Online and vice-versa. If you have purchased the wrong product, you can request a refund and then buy the one you want: https://turbotax.community.intuit.ca/community/after-you-file-questions/help/how-do-i-get-a-refund-f...
