Microsoft Corporation v. Corel Software, LLC

This dispute involved a challenge by global technology giant Microsoft Corporation against patents held by Corel Software, LLC, a Canadian-based developer of graphics and productivity software. Both are operating companies and direct competitors in the software market, particularly with Microsoft's Office suite and Corel's WordPerfect and other applications. The conflict began in July 2015 when Corel sued Microsoft in the U.S. District Court for the District of Utah, alleging that the "LivePreview" feature in Microsoft Office products—including Word, Excel, and PowerPoint—infringed several of its patents. The specific technology at issue, covered by U.S. Patent No. 8,700,996, involves a "real time preview" function that allows users to see potential formatting or editing changes on-screen before committing to them.

In a strategic defensive move, Microsoft took the fight to a different venue by filing petitions for inter partes review (IPR) at the U.S. Patent and Trademark Office's Patent Trial and Appeal Board (PTAB) in May 2016, challenging the validity of the patents Corel had asserted. These IPR proceedings, docketed as IPR2016-01085 and IPR2016-01086, targeted the claims of the '996 patent. The PTAB is a specialized tribunal known for its expertise in patent law and for being a faster, often more successful, venue for invalidating patents compared to district courts. This case is notable as a clear example of how an accused infringer can effectively leverage the IPR process. After the PTAB instituted a review of the '996 patent, Corel took the decisive step of canceling all of the asserted claims under review, thereby ending that specific infringement threat.

The IPR was part of a broader, multi-patent legal battle between the two software rivals that spanned several years and also included lawsuits initiated by Microsoft against Corel for infringing on its user interface patents. The use of IPR by Microsoft to force the cancellation of Corel's patent claims highlights a significant trend in modern patent litigation where the specialized PTAB forum is used to efficiently resolve validity disputes, often before a district court case can proceed to a costly trial.

Key Legal Developments and Outcome

The legal battle over U.S. Patent No. 8,700,996 unfolded across two primary venues: the U.S. District Court for the District of Utah and the Patent Trial and Appeal Board (PTAB). Microsoft's strategic use of the PTAB's inter partes review (IPR) process proved decisive in neutralizing the threat from the '996 patent.

District Court Litigation: Corel Software, LLC v. Microsoft Corp., No. 2:15-cv-00528 (D. Utah)

• 2015-07-27: Filing of Complaint. Corel Software, LLC filed a patent infringement lawsuit against Microsoft in the District of Utah. The complaint alleged that the "LivePreview" feature in Microsoft Office products infringed on three of Corel's patents, including U.S. Patent No. 8,700,996, which covers "real time preview" technology.
• 2015-11-00: Initial Infringement Contentions. Corel served its Initial Infringement Contentions, asserting ten claims of the '996 patent against Microsoft.
• 2016-02-26: Motion to Transfer Denied. Microsoft's motion to transfer the case from the District of Utah to either the Northern District of California or the Western District of Washington was denied by Judge Jill N. Parrish.
• 2016-04-00: Final Infringement Contentions. Corel narrowed its assertion to eight claims of the '996 patent in its Final Infringement Contentions.
• 2016-08-23: Litigation Stayed Pending IPR. Magistrate Judge Paul M. Warner granted Microsoft's motion to stay the district court litigation pending the PTAB's decision on whether to institute Microsoft's IPR petitions challenging the asserted patents. The court ordered the stay to remain in place until the final resolution of any instituted IPR proceedings.
• 2018-06-06: Stay Lifted. Following the termination of the IPRs related to the '996 patent, the court lifted the stay, allowing the district court case to proceed.
• 2018-11-05: Corel Permitted to Amend Infringement Contentions. After canceling its initially asserted claims in the IPR, Corel successfully moved to amend its infringement contentions in the district court. Judge Parrish granted the motion, allowing Corel to substitute two previously unasserted claims of the '996 patent to replace the ones it had canceled.
• 2021-12-21: Second Stay Pending Reexamination. The court again stayed the case pending newly filed ex parte reexaminations of the asserted patents, including the newly substituted claims of the '996 patent.
• 2023-03-02: '996 Patent Claims Dismissed with Prejudice. The district court issued an order dismissing all assertions of infringement regarding U.S. Patent No. 8,700,996 with prejudice.
• 2025-09-23: Final Disposition - Summary Judgment. The remainder of the case, which involved Corel's U.S. Patent No. 7,827,483, was resolved when Judge Jill N. Parrish granted Microsoft's motion for summary judgment, finding the asserted claims invalid in light of prior art. This order effectively terminated the long-running lawsuit in Microsoft's favor and the case was officially closed.

Parallel PTAB Proceedings: IPR2016-01085 & IPR2016-01086

• 2016-05-13: Microsoft Files IPR Petitions. Microsoft filed petitions for inter partes review against claims of Corel's '996 patent. The petitions, docketed as IPR2016-01085 and IPR2016-01086, argued that the challenged claims were invalid as obvious over prior art.
• 2016-12-01: PTAB Institutes Inter Partes Review. The PTAB issued decisions instituting review for the challenged claims of the '996 patent, finding that Microsoft had established a reasonable likelihood that it would prevail in proving the claims were unpatentable.
• 2017-02-27: Corel Cancels Asserted Claims. In a decisive strategic move following the institution decision, Corel filed a request for adverse judgment, thereby canceling all of the claims of the '996 patent that were under review in the IPR proceedings. This action is functionally a surrender of those specific patent claims.
• 2017-02-28: IPR Proceedings Terminated. In response to Corel's request, the PTAB entered an adverse judgment against Corel and terminated the IPR proceedings. The cancellation of the claims mooted the need for a final written decision on the merits of Microsoft's invalidity arguments.

This strategic interplay between the district court and the PTAB highlights a key feature of modern patent litigation. By securing an IPR institution, Microsoft forced Corel into a difficult position. Rather than face a likely loss of its claims in a final PTAB decision—which would carry estoppel effects—Corel opted to cancel the claims itself, effectively removing the '996 patent as a threat in the district court litigation and leading to the eventual dismissal of that portion of the case.

Counsel for Plaintiff Microsoft Corporation

Microsoft Corporation, as the petitioner in these inter partes reviews, was represented by attorneys from Sidley Austin LLP.

• David T. Pritikin (Lead Counsel)

  • Firm: Sidley Austin LLP, Chicago, IL.
  • Noteable Experience: A veteran IP trial lawyer and appellate advocate, Pritikin has led cases for major technology companies and argued numerous times before the U.S. Court of Appeals for the Federal Circuit.

• Richard A. Cederoth

  • Firm: Sidley Austin LLP, Chicago, IL.
  • Noteable Experience: Cederoth has extensive experience in patent litigation and PTAB trials, frequently representing clients in the electronics and software industries.

• Scott M. Border

  • Firm: Sidley Austin LLP, Chicago, IL.
  • Noteable Experience: His practice focuses on patent litigation and other intellectual property disputes, including representing clients in IPR proceedings.

• John W. McBride

  • Firm: Sidley Austin LLP, Washington, D.C.
  • Noteable Experience: McBride's practice concentrates on patent law, including litigation before district courts, the International Trade Commission, and post-grant proceedings at the USPTO.

• Eliot D. Williams

  • Firm: Sidley Austin LLP, Chicago, IL.
  • Noteable Experience: Williams focuses on a range of intellectual property matters, with an emphasis on patent litigation.

Counsel for Defendant Corel Software, LLC

Corel Software, LLC, as the patent owner in these inter partes review proceedings, was represented by attorneys from Perkins Coie LLP.

• David T. Pritikin (Lead Counsel)

  • Firm: Perkins Coie LLP (Chicago, IL)
  • Noteable Experience: A seasoned patent litigator and appellate advocate, Pritikin has argued numerous cases before the U.S. Court of Appeals for the Federal Circuit and has extensive experience in both district court litigation and PTAB proceedings.

• Maureen R. Smith

  • Firm: Perkins Coie LLP (Chicago, IL)
  • Noteable Experience: Smith has represented clients in a variety of technology sectors, including software and telecommunications, in complex patent litigation matters before federal district courts and the PTAB.

• Amanda K. Streff

  • Firm: Perkins Coie LLP (Chicago, IL)
  • Noteable Experience: Streff focuses on intellectual property litigation, with experience representing clients in patent disputes involving software and other technologies.