You cannot do that. The desktop software you purchased from Costco is a different product from the online program. You cannot trade in purchase you made at Costco for a product you want from TurboTax. Take the software back to Costco if you cannot/do not want to use desktop.
The "key" does not work to get online TurboTax. Only desktop.
Do you understand the difference between online and desktop?
When you use Online TurboTax, you get one return per fee. Each return needs its own account and user ID. If you use the same account and user ID for a second return, you overwrite the first one and lose it forever.
When you use Desktop TurboTax, which you install from a CD or download to your own hard drive, you can prepare and e-file multiple returns for the cost of the software. You can e-file up to 5 Federal returns—more if you mail the additional ones. If you have multiple returns to prepare for family members, Desktop is more cost effective.
This WAS VERY Annoying. Your product DOES NOT WORK with OSX!! How can the leading tax software provider not work with MAC? Furthermore, you do not make it easy to transfer the license to the online version. I purchased through Costco with email delivery for a Windows download. There were no options or indications at purchase. Even if there were, Intuit should make it easy to apply the license key to the online version. All I (and millions of others) want to do is license your product. How, after all these years, have you not solved this issue? I am going to post this complaint all over the internet if I don’t get quick remediation or a refund!
@waynerob You bought a Windows download but you have a Mac? Turbo Tax runs on Mac. Mac System Requirements
You can't apply the Desktop CD/Download purchase to Online. You have to pay for Online separately. You will have to get a refund for the Desktop program. Then you can use the Online web version. Or try to upgrade your Mac or find another computer to install it on. The CD has both Windows and Mac programs on it.
Or Call in for a refund. When you fill out the from use the word BILLING ISSUES instead of the word “refund.” Contact Customer Service 5am-9pm Pacific time 7 days a week, https://support.turbotax.intuit.com/contact
They might give you a service code to use the online version.