MoFo Wins Significant Settlement for Virtru Corp. in Data Encryption Patent Litigation Against Microsoft

Morrison Foerster successfully secured a significant settlement for its client, Virtru Corporation (“Virtru”), in patent litigation against Microsoft in the Western District of Washington. Virtru is a leading data security company that provides easy-to-use products for sharing encrypted email and files. Virtru sought damages from Microsoft for infringement of three foundational data-encryption patents invented by its co-founder, Will Ackerly, based on sales of Microsoft Office Message Encryption for Outlook (now known as Microsoft Purview). Virtru further alleged that Microsoft had willfully infringed Virtru’s patents since 2017. Microsoft agreed to a settlement on June 11, 2025—one day before jury selection was set to begin—and the parties dismissed the case on August 25, 2025.

Virtru originally brought suit against Microsoft in the Western District of Texas on March 4, 2022. As MoFo swiftly defeated three Microsoft petitions for inter partes review of Virtru’s patents, the case proceeded in Texas through claim construction, with trial scheduled for November 2023. Judge Albright denied Microsoft’s bid to transfer the case to the Western District of Washington, but Microsoft obtained mandamus relief from the Federal Circuit to compel transfer in June 2023, just five months before trial. The transferee court set trial for June 16, 2025. Microsoft subsequently moved to reopen claim construction and to move the trial date, but Virtru successfully obtained denials of both motions.

On June 6, 2025, just ten days before trial, the Court denied Microsoft’s motions for summary judgment of non-infringement and no willful infringement—in full. Microsoft agreed to settle the case five days later, ending a three-year battle. The terms of the settlement remain confidential.

The MoFo trial team was led by intellectual property litigators Mark Whitaker, Fitz Collings, and Matthew Stephens, and included Brian Nash, Rich Hung, Mary Prendergast, Stella Mao, Maryrose McLaughlin, Nate Tan, Drew Hillier, Regan Rundio, and Immanuel Elijah. PTAB practitioners Alex Yap, Mehran Arjomand, and Josh Crawford secured critical wins against Microsoft’s IPRs. Local counsel was provided by Jofrey McWilliam and Brad Keller of Byrnes Keller Cromwell LLP.