If you are claiming education credits this year, see the comment from @maglib SuperUser, above, for a link to additional information.

If you aren't claiming any education credits this year but are getting the "Can't file without Form 8863 ..." error message, it means you have a Form 8863 that transferred over from your 2016 return. The program does this to make sure you don't forget to claim a deduction, credit or income that you had in past years and may have again.

You will have to delete Form 8863 and any associated forms & worksheets that carried over from your 2016 tax file.

See: How do I delete forms in TurboTax Online?

After deleting these worksheets and statements, log out of the program. When you log back in, use the Delete a Form tool (List of Forms in My Return) to confirm Form 8863 and any associated worksheets have been removed from the list of forms in your return.