Are you doing a USA return? Costco only sells the CD in the stores. The CD has both Windows and Mac on it. Costco sells the download Desktop program online and you have to select Windows or Mac. What exactly did you buy at the store? People sometimes don't know when you buy at Costco you have to take the package to the pickup windows to get the actual CD. So they walk out with the empty package.
I buy the CD from Costco every year. And my friends buys the download from Costco online. I used the download method instead. It has more advantages over CD. Then you can also download it another computer. Once you install the CD you can't install it again like if you need to reinstall the program or install on a different computer.
There should be a card in the CD case on on the CD envelope that says how to download it and you will need the 14 or 16 digit code from it to enter.
How to download Turbo Tax instead of using the CD
https://ttlc.intuit.com/community/installing/help/i-bought-the-cd-but-my-computer-doesn-t-have-a-cd-...
And see this. How to install with a License Code
https://ttlc.intuit.com/community/tax-topics/help/activating-turbotax-cd-download-software/00/852971
I can give you my step by step instructions for both Costco CD & download for how to install it.
