Most users have no problems with buying TurboTax from Costco or other retailers. Your computer does not seem to work with the Costco download.
Since your purchase from Costco is not working on your computer, I would recommend that you purchase your program directly from Intuit. Use this link to request a refund for your Costco purchase. How do I get a refund for a TurboTax product? (intuit.ca)
Purchase your TurboTax from Intuit at this link. TurboTax® 2020-2021 Online Tax Software, Easily e-File Income Taxes Online (intuit.com)
