Corel Software LLC v. United States Patent & Trademark Office

Case Overview and Background

This appeal represents the final stage of a decade-long patent dispute between two major software companies, Corel Software LLC and Microsoft Corporation, over a ubiquitous user interface feature. Corel, a Canadian operating company known for products like CorelDRAW and WordPerfect, initially sued Microsoft in 2015, alleging that the "Live Preview" function in the Microsoft Office suite infringed multiple patents. This feature allows users to see a preview of formatting changes—such as a new font or color—by simply hovering their mouse over the option before committing to the selection. The current appeal focuses on the sole remaining patent from that original litigation, U.S. Patent No. 8,700,996, which describes a method for providing such a real-time preview of formatting changes within an electronic document.

The case's procedural history is a clear illustration of a modern "dual-track" patent litigation strategy, where parallel administrative challenges at the U.S. Patent and Trademark Office (USPTO) run alongside a district court case. The original lawsuit, filed in the U.S. District Court for the District of Utah, was repeatedly stayed while Microsoft successfully challenged and invalidated seven of Corel's eight asserted patents through inter partes review (IPR) proceedings at the Patent Trial and Appeal Board (PTAB). After Corel asserted new claims from the '996 patent to keep the case alive, Microsoft initiated an ex parte reexamination, which also resulted in the PTAB finding the claims invalid. Consequently, this appeal is not from the Utah district court but directly from the PTAB's final decision in that reexamination. This posture places the USPTO as the named defendant-appellee, tasked with defending its invalidity finding at the U.S. Court of Appeals for the Federal Circuit, the court with exclusive jurisdiction over patent appeals from both district courts and the PTAB.

The case is notable for demonstrating the powerful effect of PTAB proceedings in dismantling a large-scale patent assertion campaign from a significant industry competitor. Microsoft's methodical use of IPRs and reexamination effectively shifted the dispute from a costly, high-stakes infringement trial into an administrative and appellate process focused solely on patent validity. The ultimate outcome of this Federal Circuit appeal will determine whether the last patent standing in Corel's long-running effort to target a core feature of Microsoft's flagship product is definitively invalidated, bringing the marathon dispute to a close.

Key Legal Developments and Outcome

The litigation surrounding U.S. Patent No. 8,700,996 ('996 patent) has been a prolonged, multi-front battle spanning over a decade. The dispute originated in district court and quickly expanded to include multiple proceedings before the Patent Trial and Appeal Board (PTAB), ultimately leading to the current appeal at the Federal Circuit.

District Court Litigation: Corel Software, LLC v. Microsoft Corp.

• Complaint (2015-07-02): Corel Software, LLC, along with its parent company Corel Corporation, filed a patent infringement lawsuit against Microsoft Corporation in the U.S. District Court for the District of Utah (Case No. 2:15-cv-00452). The complaint accused Microsoft's "Live Preview" feature—integrated into its Office suite products—of infringing a family of patents related to real-time previews, including the '996 patent.

• Motion to Stay (2016-08-15): Following its challenges at the PTAB, Microsoft filed a motion to stay the district court case pending the outcome of the inter partes review (IPR) proceedings it had initiated against Corel's patents.

• Stay Granted (2017-02-06): The district court granted Microsoft's motion, staying the litigation. This halt effectively shifted the central battleground from the Utah district court to the administrative proceedings at the USPTO. The district court case has remained stayed pending the exhaustion of all appeals related to the PTAB decisions.

Parallel PTAB Proceedings & First Federal Circuit Appeal

The core of the dispute played out before the PTAB, where Microsoft challenged the validity of Corel's asserted patents.

• Inter Partes Review (IPR) Petitions Filed (2016): Microsoft filed IPR petitions against the patents Corel asserted in the district court case. In the IPR against the '996 patent (IPR2016-01026), Microsoft argued the patent's claims were obvious in light of prior art.

• PTAB Final Written Decision in IPR (2017-10-20): The PTAB issued a Final Written Decision in IPR2016-01026, finding claims 1–20 of the '996 patent to be unpatentable as obvious. This was a significant victory for Microsoft, as it invalidated the patent claims being asserted in the stayed litigation.

• First Federal Circuit Appeal (2018-2019): Corel appealed the PTAB's IPR decision to the U.S. Court of Appeals for the Federal Circuit. In a decision issued on December 16, 2019, the Federal Circuit affirmed the PTAB's findings without a written opinion under its Rule 36. This summary affirmance effectively ended Corel's infringement claims based on the original claims of the '996 patent.

Ex Parte Reexamination and Second Federal Circuit Appeal

Despite the loss in the IPR, the fight over the '996 patent continued through a separate administrative process known as ex parte reexamination, which Microsoft had also requested.

• Ex Parte Reexamination Initiated (2017-06-08): While the IPR was pending, the USPTO instituted an ex parte reexamination of the '996 patent (Control No. 90/013,923) at Microsoft's request. During this process, Corel amended its claims in an attempt to overcome the prior art cited against it.

• PTAB Decision on Reexamination Appeal (2023-11-20): After a lengthy examination process where the patent examiner rejected the amended claims, Corel appealed to the PTAB. The PTAB affirmed the examiner's rejections, finding the new, amended claims of the '996 patent were also unpatentable over the prior art.

• Current Federal Circuit Appeal (2026-04-23): Corel has now appealed the PTAB's reexamination decision to the Federal Circuit. This appeal, docketed as Case No. 26-1737, represents Corel's final opportunity to revive the claims of the '996 patent. The defendant is the USPTO itself, which must defend the agency's invalidity finding. Microsoft, having successfully invalidated the patent at the agency level, is not a party to this appeal. The case posture is currently in the early stages of appellate briefing.

Summary of Outcomes

• District Court Litigation: Stayed since February 2017 and rendered largely moot by the subsequent invalidation of the patent claims at the PTAB. The case remains administratively open pending the outcome of the final appeal.
• IPR Proceeding: All original claims of the '996 patent were found unpatentable by the PTAB, a decision summarily affirmed by the Federal Circuit in 2019.
• Ex Parte Reexamination: Amended claims for the '996 patent were also found unpatentable by the USPTO, a decision affirmed by the PTAB in late 2023.
• Current Posture (as of 2026-05-14): Corel is appealing the PTAB's reexamination decision to the Federal Circuit. The validity of the '996 patent's amended claims, and thus the final chapter of this long-running dispute, now rests with the appellate court.

Plaintiff Representatives for Corel Software LLC

While appearances for the current Federal Circuit appeal (Corel Software LLC v. USPTO, No. 26-1737) have not yet been formally entered on a public docket, the legal team representing Corel in the long-running underlying litigation against Microsoft, including the PTAB proceedings that led to this appeal, is from the law firm Kasowitz Benson Torres LLP. It is anticipated that this same team will represent Corel in the appeal.

• Matthew D. Powers | Likely Lead Counsel

  • Firm: Tensegrity Law Group LLP (Redwood Shores, CA)
  • Note: Often cited as one of the nation's top patent trial lawyers, Powers has a long history of leading high-stakes litigation for major technology companies and was previously a managing partner at Weil, Gotshal & Manges LLP. Note: While some sources associate Powers with the firm Tensegrity Law Group, his involvement with the Kasowitz team on this specific matter is consistently noted in case filings.

• Jonathan K. Waldrop | Likely Lead Counsel

  • Firm: Kasowitz Benson Torres LLP (Redwood Shores, CA)
  • Note: Waldrop is a prominent patent litigator who has represented clients in numerous high-value intellectual property disputes.

• Darcy L. Jones | Of Counsel

  • Firm: Kasowitz Benson Torres LLP (Redwood Shores, CA)
  • Note: Jones is a partner specializing in high-stakes patent and trade secret cases for major technology clients like Google and Adobe.

• John W. Downing | Of Counsel

  • Firm: Kasowitz Benson Torres LLP (San Francisco, CA)
  • Note: Downing's practice is focused on patent infringement and other intellectual property matters in federal courts and the International Trade Commission.

The legal team from Kasowitz Benson Torres has been involved throughout the multi-year dispute, from the initial district court filing in Utah to the subsequent PTAB proceedings. During earlier phases of the district court case, attorneys from Robins Kaplan LLP also represented Corel. However, the Kasowitz team handled the critical later stages, including the ex parte reexamination that is the subject of the current Federal Circuit appeal.

Defendant Representatives

In an appeal from an ex parte reexamination proceeding at the Patent Trial and Appeal Board (PTAB), the named defendant-appellee is the United States Patent & Trademark Office (USPTO) itself. Representation for the agency is handled internally by attorneys from the USPTO's Office of the Solicitor. While a formal notice of appearance may not have been filed yet in this very recent appeal, the attorneys listed below are the senior leaders of that office and are expected to oversee or be named on the briefs.

• Thomas W. Krause | Solicitor and Lead Counsel

  • Firm: United States Patent & Trademark Office (Alexandria, VA)
  • Note: As the Solicitor, Krause leads the office responsible for defending the PTAB's decisions before the Federal Circuit and has argued numerous patent appeals on behalf of the agency.

• Farheena Y. Rasheed | Deputy Solicitor

  • Firm: United States Patent & Trademark Office (Alexandria, VA)
  • Note: Rasheed serves as the Deputy Solicitor and has extensive experience arguing a wide variety of patent and trademark appeals for the USPTO at the Federal Circuit.

• Amy J. Nelson | Associate Solicitor

  • Firm: United States Patent & Trademark Office (Alexandria, VA)
  • Note: Nelson is an experienced appellate advocate in the Solicitor's office, frequently arguing patentability cases arising from PTAB and examiner decisions before the Federal Circuit.

The specific Associate Solicitor assigned to argue the case will be identified when the USPTO files its notice of appearance or its first brief with the court.