What can cause a return to be ineligible for e-filing?

A return may be considered ineligible for e-filing based on specific factors related to its content and requirements. Fiscal year tax periods can lead to ineligibility because the IRS has specific systems and procedures for processing these returns. Most taxpayers file their returns on a calendar year basis, and e-filing systems are typically designed around this framework. As a result, returns for fiscal years might need to be submitted using paper forms or through different channels, thus making them ineligible for electronic submission.

Incorrectly completed forms can indeed cause issues, but they may not directly result in e-filing ineligibility if they are corrected before submission. Lack of an ERO (Electronic Return Originator) may prevent e-filing for specific taxpayers or situations, but it's more about the assistance provided rather than the form’s eligibility. Lastly, tax returns from previous years generally have designated submission processes that are distinct from current year returns, but they are not necessarily ineligible for e-filing based on the rules that govern the filing of older returns.

Overall, the structure of the e-filing system is predominantly aligned with the calendar year periods, which is why fiscal year tax returns can lead to ineligibility for e-filing.