what options does a person have? If OPT STEM Extension is denied due to voluntary unpaid intern with professor for more than 90 days.

An OPT STEM extension requires that you be working with an employer who uses the E-Verify system. If you are working as a voluntary unpaid intern with a professor, you would not qualify for an STEM extension as the professor is likely not an E-Verify employer and all STEM work must be paid.  Thus voluntary work for more than 90 days would probably violate the law which only allows 120 days (including the STEM period) In which you can be without employment. Your options appear to be attempting to go back to school, attempting to change status to some other category, or leaving the country now and returning at some other time either with a visa or without (if under the visa waiver program).Due to the limitations of the Lawyers.com Forums, Alan Lee, Esq.'s (the "Firm") participation in responding to questions posted herein does not constitute legal advice, nor legal representation of the person or entity posting a question. No Attorney/Client relationship is or shall be construed to be created hereby. The information provided herein by the Firm is general, and requires that the poster obtain specific legal advice from an attorney. The poster shall not rely upon the information provided herein as legal advice nor as the basis for making any decisions of legal consequence.