TurboTax does not support tax year 2011.
If you are filing a 2011 tax return for a tax refund, the time to file for a refund has expired. The 2011 tax return had to be filed on or before April 15, 2015 for a tax refund.
You may be able to find the TurboTax software for 2011 at an online retailer, such as Amazon. However, there is no guarantee that any program updates will be available nor any state program downloads.
Go to this IRS website for free federal forms, schedules and instructions for prior tax years - https://www.irs.gov/forms-pubs