Help Needed: Figuring out my 60day timer start date

Hi Everyone,

This year, my H-1B application was picked and approved. Unfortunately, my company laid me off, and my last working day was October 11th.

To provide some background, I also filed for STEM OPT in March as a precaution in case my H-1B wasn't approved. However, my STEM OPT application was denied in October, and the receipt notice stated:

"A review of USCIS records indicates that on May 2x, 2024, your Form I-129, Petition for a Nonimmigrant Worker (receipt number), was approved. Your status was changed to H-1B with an employment start date of October 1, 2024. However, records indicate that your Form I-129, Petition for a Nonimmigrant Worker (receipt number), was later withdrawn on October 16, 2024. Due to the initial change of status, your SEVIS status was marked complete and not reverted to active. Since you were granted H-1B status and are no longer in F-1 status, you are ineligible for employment authorization under (c)(3)(i)(C).”

My main question is:

• When does my 60-day grace period actually begin?
  • October 11, 2024 (last working day)?
  • October 16, 2024 (date the H-1B was withdrawn)?

This clarification is important as I am currently applying for a B1/B2 visa and need to ensure my timelines are accurate.

Thank you in advance for your help!