The control number (box D) is not required to enter your W-2 or complete your tax return. Simply leave this number field blank or skip this question of TurboTax, click Skip Import and you will be directed to manually enter your W-2.
Some employers or payroll processors stated to TurboTax to require the control number for import and then left it off of the W-2.
Please see the following FAQ article for additional information. https://ttlc.intuit.com/replies/4417180