Microsoft Eyes October Reopening, Mandates Vaccines For US Office Visits ‘As we have done since the beginning of the pandemic, we continue to closely track new developments and adapt our plans as this situation evolves, keeping employee health and safety top of mind,’ a Microsoft spokesperson says in an email to CRN. By Wade Tyler Millward August 03, 2021, 05:21 PM EDT Microsoft will require proof of COVID-19 vaccination for employees, vendors and guests — with some exceptions — entering the tech giant’s U.S. buildings in September. The tech giant will also do a “full opening” for U.S. worksites no earlier than Oct. 4.