I bought the Home & Business program from Costco Online. I have Windows 10. Here's how mine went. After I bought it I got the delivery email with the Activation Code in 20 minutes.
First I updated my Windows 10 OS. Then ran a full Anti virus scan. Then paused my Anti virus.
I clicked on the bottom Download link in the email, then chose PC Download. It automatically went to my Downloads folder.
I double clicked on the file to to install it. It installed FAST! It launched and updated. Hasn't asked for the Activation code yet. It said to continue but nothing happened.
So I clicked on the Desktop Icon - got a sign in box. Had to log into my Turbo Tax account. They emailed me a code to verify me.
Then got the Activation box and entered the 16 digit code and was in.
