Will I be ineligible for pre-completion OPT? My total CPT authorization is 365 days whereas my employer letters add upto 363 days.

365 days of full time CPT negates OPT. That being said, a F-1 student may be able to dispute the total amount of time actually spent on full-time CPT. In your case, you may wish to discuss your situation with the designated school official (DSO) to see if the DSO can give you any assistance. You can also in conjunction with or separately request OPT from USCIS. You can send all documentation and explanations with the application. I express no opinion as to whether USCIS will approve the application where the claim is two days less of actual employment then was authorized on the SEVIS I-20. Due to the limitations of the Lawyers.com Forums, Alan Lee & Arthur Lee, Esqs.’ (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.