Dark Data in Law Firms: The Hidden Risk and the Information Governance Fix

by Kathryn M. Ratigan, Partner, Artificial Intelligence, Data Privacy + Cybersecurity, Robinson & Cole, LLP and Anthony Forde, Chief Revenue Officer of Future in Tech (FiT)

Law firms create and receive extraordinary volumes of information. Matter documents, email threads, chat messages, drafts, deal room exports, eDiscovery collections, recordings, transcripts, and client intake files arrive quickly and often get copied repeatedly (repeatedly) across systems. Over time, a material portion of that information becomes “dark” to the firm. It remains stored somewhere, but it is not well-understood, not consistently classified, and not reliably governed.

For law firms, dark data is not merely an IT storage problem. It’s a risk multiplier. It increases breach impact, expands discovery scope, complicates privilege protection, and undermines the firm's ability to provide defensible answers to client and regulator questions about how data is retained, protected, and disposed.

What “dark data” means in a law firm context

Dark data is information the firm stores that is not sufficiently visible, indexed, classified, or managed to support consistent controls across its lifecycle. The firm may not know it even exists, may not know who owns it, may not know which client or matter it relates to, or even whether it should be retained or disposed of.

This is different from simply “unstructured data.” Unstructured data can be well-managed if it is in the right place with the right metadata, permissions, retention, and audit controls. Dark data is unstructured, semi-structured, or even structured. Its defining feature is lack of governance and clarity.

Common examples of this in law firm include

• Shadow matter repositories on shared drives or personal drives that duplicate the document management system.
• Mailbox exports and PST-like archives created for convenience, portability, or “just in case.”
• Collaboration artifacts such as chat messages, channel files, whiteboards, meeting recordings, and transcripts.
• Client intake and materials containing sensitive identifiers collected early and retained indefinitely.
• Deal room and diligence exports stored as ZIPs and copied across workspaces.
• Old eDiscovery workspaces and productions that remain hosted or copied after the matter ends

Where dark data typically hides

Most law firms have a few predictable dark data hotspots. The specifics vary by platform, but the patterns are consistent.

1. Email and attachments
   
   • Multiple versions of the same document.
   • Long-lived mailboxes with years of matter content.
   • Local caches and exports created by individuals.
2. Shared drives and departmental file stores
   • Legacy “S drives” that continue even after a document management system (DMS) is adopted.
   • Practice group folders with inconsistent naming and access controls.
3. Collaboration platforms
   
   • Chat content, shared links, transient workspaces, guest access.
   • Meeting recordings and automatic transcripts that contain strategy and legal advice.
4. Endpoints and sync folders
   
   • Local downloads, desktop folders, and offline sync cache
   • Personal “working copies” that never return to the system of record
 
5. Vendor systems and handoffs
   
   • Hosted review platforms, file transfer tools, court reporting portals.
   • Copies retained by vendors longer than intended or retained by the firm after retrieval.

Why dark data matters and the law firm risk model

Dark data increases risk across several categories that are particularly acute for law firms. Those risks include:

1. Confidentiality and breach impact. The more unmanaged data you retain, the more you potentially expose in a cyber incident. Dark data often sits in places with weaker controls, broader access, and less monitoring. A firm can have strong security on its primary systems while still holding large amounts of sensitive information in poorly governed repositories.
2. Privilege and accidental disclosure risk. Privileged communications and attorney work product often appear in email threads, chats, draft documents, and meeting recordings. When those items are duplicated and scattered, the chance of accidental production increases. The firm also spends more time trying to determine which copy is authoritative.
3. eDiscovery and investigation cost. Discovery cost scales with volume. Dark data expands collection scope and increases processing, hosting, and review. It also makes defensible scoping harder because the firm cannot confidently say where the relevant data is, which repositories are in scope, and which are not.
4. Privacy and regulatory exposure. Dark data frequently includes personal information gathered during onboarding, employment, benefits, conflicts checks, and client intake. Retaining personal data without clear purpose and retention rules increases compliance exposure and increases the harm from any breach.
5. Client trust and contractual compliance. Clients increasingly require evidence of governance through outside counsel guidelines, security questionnaires, audits, and contractual commitments. Dark data makes it difficult to answer basic questions, such as how long data is retained, how it is disposed, and how access is reviewed.
6. Operational drag and knowledge loss. Dark data erodes search quality and retrieval speed. It also makes knowledge management harder because people do not know which version is final, whether a document is approved for reuse, or whether it can be shared across matters.

Why dark data persists in firms

Dark data is persistent because it is produced by normal, rational behavior in a high-pressure professional environment. Specifically:

• Partner autonomy and distributed working styles encourage local storage and ad hoc workflows.
• Matter lifecycle breakdown occurs when matter opening, workspace setup, and matter closing are inconsistent.
• Tool sprawl creates many places to store “one more copy” quickly.
• Unclear ownership means no one is accountable for a repository’s retention, access recertification, and cleanup.
• Paper policies without operational controls leave lawyers and staff to make individual retention decisions.

The information governance fix and principles that work for law firms

A workable law firm information governance program balances defensibility with practicality. These principles tend to produce results:

• Matter-centric organization. Make it easy to store matter content in a governed matter workspace that has the right permissions by default.
• Least privilege. Access should be limited to those who need it, then reviewed periodically.
• Data minimization. Collect only what you need and keep it only as long as required for business, ethical, contractual, and legal reasons.
• Clear systems of record. Define where the authoritative copy lives for matter documents, client communications, and firm administrative records.
• Lifecycle management. Govern data from creation through collaboration, matter close, retention, legal hold, and disposal.

A practical framework to reduce dark data

So what can you do? Here are some practical steps and actions:

1. Inventory and data mapping

Start by identifying where data lives and how it moves.

• List repositories and platforms, including collaboration, endpoints, shared drives, and vendor tools.
• Assign an owner to each repository. Ownership includes retention configuration, access reviews, and cleanup authority.
• Identify high-risk data types, including client confidential data, privileged content, and personal data.

2. Define simple classification and handling rules

Overly complex schemes fail. Start with a small number of categories that drive clear behavior.

• Client confidential. Matter and client business information.
• Firm confidential. Internal operations, HR, finance, strategy.
• Public or approved for external use. Marketing collateral, published materials.

Make the right behavior easy. Provide “what goes where” guidance so people do not default to email or personal drives.

3. Operationalize retention and defensible disposal

Retention schedules that exist only as PDFs donot reduce dark data. Retention must be implemented through platform settings and repeatable processes. Key design choices for your platform and processes:

• Define retention triggers. Common triggers include matter close, last activity, final invoice, or final disposition.
• Define exception processes. Some content may be retained for knowledge management or regulatory needs with documented approvals.
• Ensure disposal is logged. Defensible disposal is about consistency, approval, and auditabiliy.

4. Strengthen legal hold and preservation

A retention program is only credible if it can be paused reliably when needed.

• Centralize legal hold issuance and tracking.
• Ensure holds apply across repositories, not only email or the DMS.
• Preserve in place when possible to reduce copying and sprawl.

5. Tighten access controls and external sharing

Dark data thrives where access is broad and sharing is uncontrolled.

• Convert shared drives into governed workspaces where feasible.
• Remove “everyone” permissions and implement matter-based access groups.
• Review guest access and external links regularly. Expire links by default for sensitive content.

6. Monitoring and metrics

You cannot manage what you cannot see. Track indicators such as:

• growth rates by repository
• external sharing link counts and age
• data older than retention thresholds
• matters without governed workspaces
• legal hold response times

A realistic approach for firms

Your firm should start by containing the highest risks and creating clarity about where matter documents should live, rather than trying to fix every system at once. Identify the repositories that carry the most risk and volume, then publish straightforward, practical guidance on approved storage locations for matter content and day-to-day collaboration.

You should run a tightly scoped pilot to remove ROT (i.e., redundant, obsolete or trivial data) with a single practice group so you can prove value, refine the process, and avoid disrupting active matters. In parallel, reduce obvious high-risk behaviors such as unmanaged exports and long-lived external links, and treat collaboration content like chats and recordings as in-scope because it can be as sensitive as formal documents.

From there, build durable governance and controls that fit how legal work actually happens.

Common pitfalls to avoid include implementing a complex classification scheme that nobody uses, overlooking collaboration content, confusing backups with archives since backups are for recovery while archives require indexing, retention, and access controls, failing to enforce matter closing discipline which prevents retention from starting, and leaving shared drives or legacy systems without an accountable owner since orphaned repositories quickly become dark and risky.

Selecting the right partners to make dark data remediation stick

For many firms, reducing dark data requires more than internal policy and IT effort. The work often spans document management, Microsoft 365, collaboration tools, endpoints, eDiscovery, retention engines, and vendor-hosted matter platforms. That is where strong technology and vendor partners, plus experienced outside counsel, can materially accelerate progress and reduce missteps.

In technology and vendor partners, your firm should look for:

• Proven law firm experience and references. Prioritize providers that have implemented information governance, retention, and legal hold programs in law firm environments with similar practice mixes, client confidentiality expectations, and matter lifecycle realities.
• Cross-repository visibility and defensible reporting. Favor tools and service partners that can identify data across key locations, including email, collaboration platforms, shared drives, endpoints, and common vendor systems, then produce audit-ready reports that support defensible decisions.
• Retention, legal hold, and disposition that work together. Ask specifically how retention policies are applied, how holds suspend disposition across repositories, and how the system demonstrates preservation, exceptions, and deletion logs when challenged.
• Security and access governance capabilities. Strong partners can help implement least privilege at scale with practical mechanisms for access reviews, external sharing controls, and automated link expiration, plus monitoring that highlights risky exposures.
• Data minimization and ROT reduction services. Effective partners bring repeatable playbooks for targeted cleanup projects, including scoping, sampling, stakeholder approvals, workflow design, and change management. They should be able to support a pilot and then scale.
• Clear ownership model and operational handoff. Insist on a plan that leaves your firm with named repository owners, documented workflows, and sustainable metrics. Avoid solutions that depend on permanent consulting support to remain functional.
• Contract terms aligned with confidentiality and disposal. Vendor agreements should support your governance goals with clear provisions for data ownership, permitted use, subcontractors, retention and deletion timelines, return or destruction at matter close, and audit rights where appropriate.

Outside legal counsel can also assist your team tackle dark data. Even sophisticated firms benefit from independent legal guidance when dark data intersects with privilege, privacy, regulatory requirements, and client contractual commitments. Outside counsel can:

• Align retention and disposition with legal and ethical duties. Counsel can help translate obligations into practical retention triggers, exception pathways, and defensible disposal practices that can be implemented technically.
• Reduce privilege and waiver risk. Counsel can advise on how to treat high-risk collaboration content, drafts, recordings, and transcripts. They can also help structure processes to reduce accidental disclosure risk during cleanup and migration.
• Support incident readiness and regulatory posture. Dark data remediation should complement breach response planning and compliance expectations. Counsel can help ensure the program improves defensibility before a client audit, regulator inquiry, or litigation event.
• Strengthen vendor contracting and oversight. Counsel can review and negotiate vendor terms that often drive dark data accumulation, including hosted platforms, eDiscovery vendors, and collaboration or file transfer tools.
• Document decisions for defensibility. A well-documented rationale for classification rules, retention triggers, exceptions, and pilot outcomes can be critical later. Counsel can help shape that record so it is coherent and supportable.

Conclusion

Dark data is not an unavoidable byproduct of legal work. It is a governance gap that can be measured, prioritized, and reduced. By establishing clear systems of record, implementing retention and legal hold across the repositories where lawyers actually work, tightening access and sharing, and disposing of ROT in a consistent and logged way, firms can materially lower breach impact and discovery cost while strengthening privilege protection. The most successful programs pair practical internal ownership with the right technology and service partners, and they involve experienced outside counsel to ensure that retention, preservation, and vendor practices remain defensible as client expectations and regulatory scrutiny increase.