DCT

8:23-cv-02415

X1 Discovery Inc v. Microsoft Corp

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Amended Complaint
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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 8:23-cv-02415, C.D. Cal., 09/11/2026
  • Venue Allegations: Venue is alleged to be proper because Microsoft transacts business in the district and has regular and established places of business in Irvine, Costa Mesa, and Los Angeles, California.
  • Core Dispute: Plaintiff alleges that Defendant’s computer hardware and software products, including Windows, Microsoft 365, and SharePoint, infringe four patents related to incremental, "search-as-you-type" technology.
  • Technical Context: The technology at issue involves methods for incrementally displaying and refining search results in real-time as a user types a query, a functionality that is now fundamental to modern operating systems and applications.
  • Key Procedural History: The complaint details an extensive prosecution history, alleging that Microsoft repeatedly cited Plaintiff's patents and published applications as prior art against its own patent applications between 2007 and 2016, and ultimately abandoned several of those applications. The complaint also references direct collaboration discussions between the parties in 2017-2018 and an ITC Investigation involving one of the asserted patents.

Case Timeline

Date Event
2002-09-03 Priority Date for ’035, ’139, and ’977 Patents
2003-02-20 Priority Date for ’490 Patent
2005-05-16 Microsoft launches "MSN Search Toolbar with Windows® Desktop Search"
2007-05-18 Plaintiff's patent publication cited by USPTO examiner against a Microsoft application
2008-05-06 U.S. Patent No. 7,370,035 Issues
2008-12-04 Microsoft cites the issued ’035 Patent in an Information Disclosure Statement
2013-07-30 U.S. Patent No. 8,498,977 Issues
2015-06-24 USPTO makes the ’977 Patent of record in a Microsoft patent application
2017-04-25 U.S. Patent No. 9,633,139 Issues
2017-01-01 Start of alleged collaboration discussions between X1 and Microsoft (approx. date)
2020-02-04 U.S. Patent No. 10,552,490 Issues
2023-12-19 Complaint filed in ITC Investigation No. 337-TA-1389 regarding '977 Patent
2026-09-11 Complaint Filing Date

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 7,370,035 - "Methods and Systems for Search Indexing"

  • Patent Identification: U.S. Patent No. 7,370,035, "Methods and Systems for Search Indexing," issued May 6, 2008.

The Invention Explained

  • Problem Addressed: The patent's background section describes conventional search engines as "slow and cumbersome," requiring a user to type a full search term, click a button, and then review a static list of results Compl. ¶55 ’035 Patent, col. 1:32-39 This process was described as tedious and inefficient for refining searches Compl. ¶55 ’035 Patent, col. 1:35-39
  • The Patented Solution: The invention is a method for "incremental or reactive searching" where results are provided or narrowed "substantially immediately after each character in a search string is entered by the user" Compl. ¶56 ’035 Patent, col. 2:13-16 This provides immediate feedback to the user Compl. ¶56 The patent specifically teaches a method of using a first and second search string within a single search field, separated by a character, to incrementally locate documents containing words that begin with those respective strings Compl. ¶57 ’035 Patent, claim 1
  • Technical Importance: This "search-as-you-type" approach represented a significant improvement in user interface design, allowing for much faster and more accurate access to information by providing real-time feedback Compl. ¶56 ’035 Patent, col. 2:16-21

Key Claims at a Glance

  • The complaint asserts independent method claim 1 (indirectly) and independent apparatus claim 10 (directly) Compl. ¶¶85-87
  • The essential elements of independent claim 1 include:
    • receiving a first string in a first search field;
    • in response, incrementally locating a first group of documents having a word that begins with the first string;
    • receiving a second string in the same search field, separated from the first by a string separator character;
    • in response, incrementally locating a second group of documents having a word that begins with the second string;
    • identifying documents that are included in both the first and second groups; and
    • displaying an indication of the identified documents.

U.S. Patent No. 9,633,139 - "Methods and Systems for Search Indexing"

  • Patent Identification: U.S. Patent No. 9,633,139, "Methods and Systems for Search Indexing," issued April 25, 2017.

The Invention Explained

  • Problem Addressed: Like the ’035 Patent, the ’139 Patent addresses the slow and cumbersome nature of conventional search technologies, which required users to develop "deliberate and tedious search strings" Compl. ¶63 '139 Patent, col. 2:1-4
  • The Patented Solution: The patent discloses a similar method of incremental searching that provides immediate feedback as a user types Compl. ¶64 '139 Patent, col. 2:19-22 A key feature of the patented method is updating search results to identify documents where the first and second partial search strings are "non-adjacent" Compl. ¶65 '139 Patent, claim 1 This allows for finding documents where the search terms appear, but not necessarily as a contiguous phrase.
  • Technical Importance: This technology improves search by allowing users to find more relevant documents where search terms are related but not directly next to each other, enhancing the power of multi-term queries Compl. ¶66

Key Claims at a Glance

  • The complaint asserts independent method claim 1 (indirectly) and independent system claim 23 (directly) Compl. ¶¶98-100
  • The essential elements of independent claim 1 include:
    • receiving a first partial search string and a second partial search string in a single search field, separated by a string separator;
    • incrementally searching for a first group of documents corresponding to the first partial string;
    • in response to receiving the second string, incrementally searching for a second group of documents corresponding to the second partial string; and
    • updating search results by identifying documents included in both groups, "wherein the first partial search string and the second partial search string are non-adjacent in at least one of the identified documents."

U.S. Patent No. 10,552,490 - "Methods and Systems for Search Indexing"

  • Patent Identification: U.S. Patent No. 10,552,490, "Methods and Systems for Search Indexing," issued February 4, 2020.
  • Technology Synopsis: The ’490 Patent addresses the same limitations of conventional search Compl. ¶71 It claims a computing system, rather than a method, comprising processors and storage media storing a specific "index data structure" that associates character strings with files. The system performs incremental searches on this index, including identifying documents where first and second search strings are "non-adjacent" Compl. ¶¶72-74 ’490 Patent, abstract
  • Asserted Claims: Independent system claim 1 Compl. ¶112
  • Accused Features: The accused software products (Windows Search, Microsoft 365 Search, SharePoint Search) running on the accused computer hardware are alleged to form the infringing system Compl. ¶¶112-114

U.S. Patent No. 8,498,977 - "Methods and Systems for Search Indexing"

  • Patent Identification: U.S. Patent No. 8,498,977, "Methods and Systems for Search Indexing," issued July 30, 2013.
  • Technology Synopsis: The ’977 Patent also seeks to improve upon slow, conventional search Compl. ¶79 Its disclosed solution is the integration of index-based search, incremental search, and "text based command processing into a single system" Compl. ¶81 ’977 Patent, abstract This allows a unified search field to be used both for searching content and for executing computer commands, with the system first determining if an input string is a command before initiating a search (Compl. ¶82).
  • Asserted Claims: Independent system claim 19 (directly) and independent method claim 1 (indirectly) Compl. ¶124
  • Accused Features: The search functionality in the accused products is alleged to integrate both document search and command execution in a single interface Compl. ¶¶124-126

III. The Accused Instrumentality

Product Identification

  • The complaint identifies two categories of accused instrumentalities:
    1. Accused Computer Products: A range of Microsoft Surface laptop and tablet devices Compl. ¶50
    2. Accused Software Products: Microsoft Windows 10 and 11 (specifically Windows Search and File Explorer Search), Microsoft 365 (specifically Microsoft 365 Search), and SharePoint (including SharePoint Server and SharePoint Online) Compl. ¶51

Functionality and Market Context

  • The complaint alleges that these products all include search functionality that "incrementally searches documents or files" as a user types into a search bar Compl. ¶86 Compl. ¶99 This feature is positioned as a core component of the user experience within Microsoft's flagship operating system and productivity software suites, allowing users to find files, emails, and other data stored both locally and across cloud services like OneDrive and SharePoint Compl. ¶86

No probative visual evidence provided in complaint.

IV. Analysis of Infringement Allegations

’035 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
a method of performing a search comprising: receiving a first string in a first search field; Users of the Accused Products type a first search word or string into a search interface, such as the Windows Search bar. ¶87 col. 2:50-51
in response to receiving the first string, incrementally locating a first group of documents that has at least a first word that begins with the first string; As the user types the first string, the Accused Products' search functionality displays a dynamically updated list of documents containing words that begin with that string. ¶86 col. 2:51-53
receiving a second string in the first search field, wherein the first and second strings are separated by a string separator character in the first search field; The user types a separator (such as a space) followed by a second word or string into the same search interface. ¶87 col. 2:54-57
in response to receiving the second string, incrementally locating a second group of documents that has at least a second word that begins with the second string and identifying one or more documents that are included in each of the first and second groups of documents; As the user types the second string, the search results are further filtered in real-time to a list of documents that contain words beginning with both the first and second strings. ¶86 col. 2:57-63
and displaying an indication of one or more of the identified one or more documents that are included in each of the first and second groups of documents. The filtered list of identified documents is displayed to the user in the search interface. ¶87 col. 2:64-67

’139 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
a method of performing a search... comprising: receiving a first partial search string in a first search field; receiving a second partial search string in the first search field, wherein the first and second partial search strings are separated by a string separator character... Users of the Accused Products type a first and second search term, separated by a character like a space, into a single search bar. ¶100 col. 20:23-28
incrementally searching for a first one or more documents... each including at least one string that corresponds to the first partial search string; As the user types the first term, the search functionality performs an incremental search and displays a first set of results. ¶99 col. 20:29-33
in response to receiving the second partial search string, incrementally searching for a second group of documents each including at least one string that corresponds to the second partial search string; As the user types the second term, the functionality performs a second incremental search for documents matching the second term. ¶99 col. 20:34-39
and updating search results... by identifying one or more documents included in both the first group... and the second group..., wherein the first partial search string and the second partial search string are non-adjacent in at least one of the identified documents. The functionality updates the results list to show only documents that contain both search terms, where those terms are not required to be next to each other in the document. ¶106 col. 21:6-15
  • Identified Points of Contention:
    • Scope Questions: The case may turn on the specific definition of "incrementally locating" and "incrementally searching." A question for the court will be whether the accused products' real-time update functionality performs the specific steps of the claimed methods, or if it operates via a technically distinct, non-infringing process. The term "substantially immediately" (recited in the specification) may also be a point of dispute regarding the timing of the updates.
    • Technical Questions: For the ’139 Patent, a key question will be one of proof: what evidence demonstrates that the accused search functionality performs the specific limitation of identifying documents where terms are "non-adjacent"? Microsoft may argue that its search is a standard Boolean "AND" search that naturally returns documents where terms may be adjacent or non-adjacent, without performing the specific "non-adjacent" identification step as claimed.

V. Key Claim Terms for Construction

For the ’035 and ’139 Patents

  • The Term: "incrementally locating" / "incrementally searching"
  • Context and Importance: This term is the technological core of the asserted patents. Its construction will be critical for determining infringement. Practitioners may focus on this term because its scope will define whether any "search-as-you-type" feature infringes, or only those that operate in the specific manner disclosed in the patents.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The specification states that "search results are provided or narrowed substantially immediately after each character in a search string is entered," which may support a broader construction covering any search that updates results in real-time as a user types '035 Patent, col. 2:13-16
    • Evidence for a Narrower Interpretation: The detailed description and figures illustrate specific index architectures and search processes (e.g., ’490 Patent, Fig. 2B). This could support a narrower construction limited to systems that utilize these specific disclosed methods for achieving the incremental search.

For the ’139 and ’490 Patents

  • The Term: "non-adjacent"
  • Context and Importance: This limitation distinguishes the later patents from the earlier ’035 Patent and is central to the infringement allegation for the ’139 and ’490 Patents. Its definition will determine whether a standard search for two separate keywords infringes.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The claim language states "wherein the first partial search string and the second partial search string are non-adjacent in at least one of the identified documents" '139 Patent, claim 1 This could be interpreted as describing a characteristic of the result of the search, meaning any search that returns a document where the terms are not next to each other would meet the limitation.
    • Evidence for a Narrower Interpretation: A defendant may argue that "non-adjacent" must be read in light of the full claim context, which describes a multi-step process of "updating... by identifying." This could support an interpretation that requires a specific algorithmic step of affirmatively identifying documents where terms are non-adjacent, rather than merely returning them as part of a general keyword search.

VI. Other Allegations

  • Indirect Infringement: The complaint alleges that Microsoft induces infringement by providing customers with installation manuals, troubleshooting guides, and product tutorials that instruct and encourage end-users to use the accused search functionality Compl. ¶92 Compl. ¶106 Contributory infringement is alleged on the basis that the infringing search functionality is a material part of the accused products and is not a staple article of commerce suitable for substantial non-infringing uses Compl. ¶93 Compl. ¶107
  • Willful Infringement: The complaint makes extensive allegations to support willfulness. It claims Microsoft had pre-suit knowledge of the patents based on: (1) Microsoft's own patent prosecution activities between 2007-2016, where it repeatedly cited Plaintiff’s patent family as prior art and allegedly abandoned applications after rejections over that art Compl. ¶¶23-41; (2) direct business communications and meetings in 2017-2018 where X1 allegedly provided Microsoft with literature referencing the patents-in-suit Compl. ¶42; and (3) knowledge from a prior ITC Investigation involving the ’977 patent Compl. ¶128

VII. Analyst’s Conclusion: Key Questions for the Case

  1. Claim Scope and Infringement: A core issue will be one of definitional scope: can the term "incrementally locating/searching," as defined by the patents' specifications, be construed to cover the specific technical implementation of the "search-as-you-type" features in Microsoft's Windows and Microsoft 365 products? The case may depend on whether there is a fundamental match or mismatch in the underlying technical operation of the indexing and query-updating processes.

  2. Validity in Light of Prosecution History: A central validity question will be one of non-obviousness. The complaint extensively details Microsoft's own patent prosecution history, where it allegedly failed to overcome Plaintiff's patent family as prior art. This raises the question of whether Microsoft can now credibly argue that the asserted claims are obvious, and whether its prior positions before the USPTO could have any preclusive or estoppel-like effect on its litigation defenses.

  3. Willfulness and Damages: A key evidentiary battle will focus on willful infringement. The allegations of Microsoft’s long-standing awareness of the patents through its own R&D and patent prosecution efforts, coupled with direct communications, create a significant question for the court. The outcome will heavily influence the potential for enhanced damages if infringement is found.