Are you using the Windows version of the desktop product (CD/download?) If so, try the troubleshooting steps in this TurboTax help article.
Every computer has a unique combination of components, settings, programs, services, and users. This means TurboTax can install and run flawlessly on one computer, but another computer's configuration can cause conflicts when installing, launching, or running TurboTax.
See this help article for problems with importing. In some cases, it's easier to manually enter the data.
A blank, non-functioning, incomplete, or buffering activation screen may be related to either a screen resolution or scaling problem in your Windows settings.
In Windows 10 to get to the scaling or resolution settings click the Windows start button in lower left corner, then choose Settings (gear icon), then System, then Display.
First try the scaling setting. In your Windows Settings do you have scaling set to a higher value than the normal 100%? If so, change it back to 100%. Once the license code is entered and activated, you can later change your scaling setting back like it was.
If lowering the scaling to 100% didn't help, then it may be screen resolution. Try a lower screen resolution such as 800x600. Once you get the license activated, you can revert your resolution setting back like it was.
NOTE: If you happen to encounter a similar issue with a popup screen later on in some section of the program, you may have to temporarily perform this maneuver again.
Try clearing your cache and cookies for problems with functions that have an online component. If after trying all of the options mentioned you still have the same problems:
See this help article and this one for instructions on how to contact TurboTax customer support depending on which product you are using.
**Say "Thanks" by clicking the thumb icon in a post
**Mark the post that answers your question by clicking on "Mark as Best Answer"