The tech giant declined to set a new reopening date but promised to give employees 30 days' notice.
"Given the uncertainty of Covid-19, we've decided against attempting to forecast a new date for a full reopening of our US work sites in favor of opening US work sites as soon as we're able to do so safely based on public health guidance," Jared Spataro, Microsoft (MSFT)'s corporate vice president for modern work, said in a blog post.
"The evolving Delta variant is compelling many of us to adjust plans for reopening worksites," Spataro wrote. "It's a stark reminder that this is the new normal. Our ability to come together will ebb and flow."
Microsoft joins a growing list of major companies forced to delay their back-to-office plans. Wells Fargo, BlackRock, CNN, and others pushed back their plans to reopen offices after Labor Day until October. Amazon, Facebook, and other tech companies have said they won't be back in the office until 2022 at the earliest.