Microsoft 365 for Law Firms

Law firms rely on technology to manage confidential documents, communicate with clients, collaborate on matters and meet important deadlines.

Microsoft 365 brings email, document management, communication, device security and compliance tools together within one cloud-based environment.

Applications such as Outlook, Word, Excel, Teams, SharePoint and OneDrive can help legal professionals work from the office, court, home or a client location without losing access to the information they need.

However, simply purchasing Microsoft 365 licences does not automatically create a secure or well-organised legal practice.

User permissions, sharing controls, device management, data protection and cybersecurity settings must all be configured properly. Without suitable planning, Microsoft 365 can become cluttered, difficult to manage and potentially expose sensitive client information.

What Is Microsoft 365?

Microsoft 365 is a collection of cloud services and productivity applications designed to support communication, collaboration, information management and cybersecurity.

Depending on the subscription selected, it may include:

• Outlook and Exchange Online
• Word
• Excel
• PowerPoint
• Microsoft Teams
• SharePoint
• OneDrive
• Microsoft Lists
• Microsoft Forms
• Power Automate
• Microsoft Entra ID
• Microsoft Intune
• Microsoft Defender
• Microsoft Purview
• Microsoft 365 Copilot

The features available depend on the licence assigned to each user. Microsoft’s Business plans are intended for organisations with up to 300 users, while larger firms can use Microsoft 365 enterprise subscriptions. (Microsoft)

Why Is Microsoft 365 Suitable for Law Firms?

Legal professionals need secure access to email, documents, calendars and case information from several locations.

Microsoft 365 can provide a common platform for:

• Client communication
• Matter collaboration
• Document creation
• Secure file sharing
• Remote working
• Meeting management
• User access control
• Device management
• Data classification
• Compliance investigations
• Business continuity

Using one integrated platform can reduce the number of separate systems employees need to manage.

It can also make it easier for the firm’s IT provider to apply consistent security policies across accounts, devices and information.

The benefits depend on how well the environment is designed. A poorly structured Microsoft 365 tenant can make information difficult to find and give employees access to documents they do not genuinely need.

Professional Email With Exchange Online

Exchange Online provides business email, shared calendars, contacts and mailbox management through Microsoft 365.

Law firms can use it for:

• Individual solicitor mailboxes
• Shared departmental mailboxes
• Court and completion calendars
• Meeting-room booking
• Centralised contacts
• Mobile email access
• Email retention
• Mail flow and security policies

Shared mailboxes can be useful for addresses such as:

• Conveyancing@
• Litigation@
• Accounts@
• Enquiries@
• Complaints@
• Compliance@

They allow authorised employees to manage messages from a common address without sharing one password.

Access should be reviewed regularly so employees do not retain access to mailboxes belonging to departments or matters they no longer work with.

Protecting Law Firm Email

Email is one of the most common routes used to target legal practices.

An attacker may impersonate a client, solicitor, bank, property agent or senior partner. They may attempt to steal passwords, redirect payments or persuade an employee to open a malicious attachment.

Microsoft 365 can support email protection through features such as:

• Spam and malware filtering
• Anti-phishing policies
• Safe Links
• Safe Attachments
• Impersonation protection
• Mailbox auditing
• Quarantine
• External sender identification

Microsoft Defender for Office 365 can extend protection across email, Teams, OneDrive and SharePoint. Its supported capabilities include checking links and scanning attachments for potentially malicious content. (Microsoft)

The exact protection available depends on the licences and policies in place.

Email security should also be supported by SPF, DKIM and DMARC. These technologies help receiving organisations verify whether a message using the law firm’s domain has been sent through an authorised system.

Multi-Factor Authentication

Every law firm should enable multi-factor authentication for Microsoft 365.

A password can be stolen through phishing, reused from another website or exposed in a data breach.

Multi-factor authentication requires the person signing in to provide an additional form of verification. This may involve an authenticator application, biometric verification or a physical security key.

Microsoft 365 business subscriptions include security defaults, which can enable baseline multi-factor authentication protections. Microsoft 365 Business Premium also includes Microsoft Entra ID Plan 1, supporting more detailed Conditional Access policies. (Microsoft Learn)

Employees should be trained never to approve an authentication request they did not initiate.

An unexpected request may indicate that a criminal already knows the user’s password.

Conditional Access

Conditional Access allows a law firm to create rules governing how Microsoft 365 can be accessed.

Policies can consider signals such as:

• User identity
• Location
• Device compliance
• Application
• Sign-in risk
• Type of access
• Administrator status

The firm might require stronger authentication when someone signs in from an unfamiliar location or prevent access from an unmanaged device.

Microsoft describes Conditional Access as its Zero Trust policy engine, bringing together identity and device signals before applying the organisation’s access rules. (Microsoft Learn)

Conditional Access should be introduced carefully.

A poorly configured policy could lock employees or administrators out of important systems. Policies should be tested before they are applied throughout the firm, and emergency access arrangements should be maintained securely.

Microsoft Teams for Legal Collaboration

Microsoft Teams can provide a central location for meetings, messages and collaborative work.

Law firms may use Teams for:

• Internal department communication
• Matter discussions
• Client meetings
• Project collaboration
• Training
• Video calls
• File sharing
• Internal announcements

Teams can reduce the need for long internal email conversations, but it requires suitable governance.

Without clear rules, a firm may create hundreds of Teams with unclear names, duplicate information and unknown owners.

Each Team should have:

• A clear purpose
• Consistent naming
• At least two suitable owners
• Appropriate membership
• Defined guest-access rules
• A review date
• An archive process

Employees should understand that a Team is not automatically private merely because its name relates to a particular matter. Membership and file permissions must be checked.

SharePoint for Matter and Document Management

SharePoint provides cloud-based sites and document libraries that can be used to organise business information.

A law firm might use separate SharePoint locations for:

• Departments
• Internal policies
• Precedent documents
• Marketing
• Compliance
• Human resources
• Projects
• Knowledge management

SharePoint can provide:

• Document version history
• Search
• Permissions
• Metadata
• Approval workflows
• Retention controls
• External sharing
• Co-authoring

It may also support legal matter information, although firms should consider whether their specialist case-management or document-management system remains the appropriate primary location for client files.

The structure should be agreed before large volumes of information are migrated.

Moving disorganised shared-drive folders into SharePoint without improving the structure may simply transfer the existing problems into the cloud.

OneDrive for Individual Working Files

OneDrive provides cloud storage associated with an individual employee’s Microsoft 365 account.

It can be useful for:

• Personal working documents
• Drafts
• Files that are not yet ready for a shared location
• Secure access across managed devices
• Temporary collaboration

OneDrive should not normally become the permanent home of important matter documents that several employees require.

When important information is stored only in one solicitor’s OneDrive, it may be difficult for colleagues to locate and manage.

Final documents and shared business information should normally be moved into the firm’s approved matter-management, document-management or SharePoint location.

Secure External File Sharing

Law firms frequently need to exchange documents with clients, counsel, experts and other parties.

Sending confidential attachments through email can create several risks:

• The wrong file may be attached
• The message may be sent to the wrong recipient
• The document may remain in several mailboxes
• Access cannot easily be withdrawn
• The recipient may forward it
• File-size limits may be exceeded

SharePoint and OneDrive can provide controlled sharing links.

Depending on the configuration, a firm may be able to:

• Restrict access to named recipients
• Set expiry dates
• Prevent downloading
• Require authentication
• Remove access later
• Review sharing activity

External sharing should not be left entirely to individual preference.

The firm should define which information can be shared, which link types are permitted and when a more controlled client portal is required.

Managing Client Confidentiality

Microsoft 365 security follows the permissions configured by the organisation.

It cannot determine by itself whether a solicitor should have access to a specific client matter.

The firm must establish suitable rules governing:

• SharePoint membership
• Teams membership
• Shared mailbox access
• OneDrive sharing
• Guest accounts
• Administrator permissions
• Former employee accounts
• Third-party access

Access should follow the principle of least privilege.

Employees should receive the information needed for their work without automatically being given access to every department or client matter.

Permissions should be reviewed when someone changes department, moves role, completes a project or leaves the firm.

Sensitivity Labels

Microsoft Purview sensitivity labels can help classify and protect information according to its sensitivity.

A firm could create classifications such as:

• Public
• Internal
• Confidential
• Client Confidential
• Highly Confidential

Depending on licensing and configuration, labels may apply protections including:

• Encryption
• Access restrictions
• Visual markings
• Sharing controls
• Content protection

Microsoft Purview provides tools designed to govern, protect and manage information across an organisation. (Microsoft Learn)

Labels should be easy for employees to understand.

Creating too many classifications can lead to confusion and inconsistent use. The firm should begin with a manageable structure supported by practical training.

Data-Loss Prevention

Data-loss prevention policies can help identify and restrict the inappropriate sharing of sensitive information.

A policy might detect:

• Financial information
• Passport details
• National Insurance numbers
• Bank account information
• Personal data
• Confidential documents

Depending on the configuration, Microsoft 365 may warn the employee, block the action or require a justification.

Data-loss prevention should be introduced carefully.

Overly restrictive policies can interfere with legitimate legal work, while weak policies may fail to provide meaningful protection.

The firm should identify its highest-risk information and test policies with appropriate departments before wider implementation.

Retention and Records Management

Law firms need clear policies governing how long different types of information are retained.

Retention requirements may depend on:

• Matter type
• Client instructions
• Limitation periods
• Regulatory duties
• Insurance requirements
• Legal holds
• Data-protection principles

Microsoft Purview retention capabilities can help retain or remove information according to defined rules, subject to the organisation’s licences and configuration. (Microsoft Learn)

Technology should support the firm’s approved retention policy rather than define it.

Legal, compliance and data-protection specialists should determine the required retention periods before the technical rules are applied.

Microsoft Purview eDiscovery

Electronic discovery involves identifying and managing electronically stored information for investigations or legal proceedings.

Microsoft Purview eDiscovery can work with supported content from services including:

• Exchange Online
• Microsoft Teams
• Microsoft 365 Groups
• OneDrive
• SharePoint
• Viva Engage

Microsoft describes Purview eDiscovery as a way to identify, review and manage electronic information that may be required for investigations and legal cases. (Microsoft Learn)

The available features depend on the Microsoft 365 and Purview licences held by the firm.

eDiscovery should be configured and operated by authorised individuals using documented procedures.

Device Management With Microsoft Intune

Law firm information may be accessed from laptops, desktops, tablets and mobile phones.

Microsoft Intune can help centrally manage supported devices and applications.

Policies may be used to:

• Require device encryption
• Apply secure screen locks
• Configure applications
• Deploy security settings
• Check device compliance
• Protect mobile data
• Remove business information
• Restrict access from insecure devices

Microsoft 365 Business Premium includes Intune capabilities and allows administrators to review device health and take supported security actions through the Microsoft security platforms. (Microsoft Learn)

Device management is particularly important for remote and hybrid workers.

A solicitor working away from the office should receive the same security policies as someone connected to the firm’s internal network.

Endpoint Protection

Every device accessing legal information should be protected by centrally managed endpoint security.

Modern endpoint protection can detect suspicious behaviour rather than relying solely on signatures for known viruses.

It may help identify:

• Malware
• Ransomware
• Suspicious scripts
• Credential theft
• Unusual application behaviour
• Potentially compromised devices

Microsoft 365 Business Premium includes Defender for Business, alongside identity and device-management capabilities intended for small and medium-sized organisations. (Microsoft Learn)

Security alerts must be actively monitored.

Installing a protection product without assigning responsibility for its alerts can leave serious threats uninvestigated.

Supporting Remote and Hybrid Work

Microsoft 365 allows employees to access authorised information from different locations.

This can improve flexibility for solicitors attending court, visiting clients or working from home.

Secure remote work should include:

• Managed devices
• Multi-factor authentication
• Conditional Access
• Device encryption
• Endpoint protection
• Secure Wi-Fi guidance
• Restricted local storage
• Controlled file sharing
• Automatic security updates
• Remote support

Employees should not routinely transfer client information to personal email accounts, unapproved cloud storage or unmanaged devices.

The firm should define what is permitted and provide secure tools that are practical to use.

Business Continuity

Microsoft 365 can reduce dependence on one office or physical server.

Employees may continue accessing cloud-hosted services from another location when the office is unavailable.

However, cloud services do not remove the need for business-continuity planning.

The firm should consider:

• What happens during an internet outage
• How employees communicate if Microsoft 365 is unavailable
• Which systems are most important
• How data will be recovered
• Whether alternative devices are available
• How suppliers are contacted
• How court and client deadlines are protected

Microsoft 365 should form part of the firm’s continuity plan rather than being treated as the complete plan.

Microsoft 365 Backup

Microsoft 365 includes availability, retention and recovery capabilities, but the firm should establish its own recovery requirements.

Questions should include:

• Which information needs additional backup?
• How long should deleted information be retained?
• How quickly must a mailbox or SharePoint site be restored?
• Who can delete recovery data?
• How are restores requested?
• When was recovery last tested?

Many organisations choose a separately managed Microsoft 365 backup service to provide additional retention and recovery options.

The correct approach will depend on the firm’s risk, contractual obligations and business-continuity requirements.

A backup should be monitored and tested rather than assumed to work.

Microsoft 365 Copilot for Law Firms

Microsoft 365 Copilot can help legal professionals draft, summarise, search and analyse information within supported Microsoft 365 applications.

Possible uses include:

• Summarising email threads
• Preparing meeting notes
• Drafting internal documents
• Comparing information
• Creating presentation outlines
• Finding approved policies
• Producing initial client updates

Copilot works within the permissions already applied to Microsoft 365 information.

This makes permission reviews particularly important. When an employee already has excessive access to SharePoint or Teams information, AI may make that information easier to discover.

The firm should complete a readiness review before introducing Copilot.

This should include:

• SharePoint permissions
• External sharing
• Teams membership
• Data classification
• Sensitivity labels
• Employee training
• AI usage policies
• Human review requirements

AI-generated content can be inaccurate and should not be relied upon without professional verification.

Choosing the Right Microsoft 365 Licence

The most suitable licence will depend on the size of the firm and the security, compliance and device-management features required.

Microsoft 365 Business Premium is often considered by smaller and medium-sized organisations because it combines productivity applications with Microsoft Entra ID Plan 1, Conditional Access, Intune and Defender for Business. Microsoft’s Business plans have a maximum of 300 users across the organisation. (Microsoft Learn)

Larger firms or organisations needing more advanced compliance, identity and security capabilities may require enterprise subscriptions or additional Microsoft Defender and Purview licences.

Licences should be selected according to the required controls rather than only the applications employees want to use.

The firm should also review licences regularly to identify inactive accounts, unnecessary subscriptions and users who have not been given the protection required for their role.

Common Microsoft 365 Mistakes Made by Law Firms

Microsoft 365 can create risks when it is introduced without suitable governance.

Common mistakes include:

• Leaving multi-factor authentication disabled
• Giving too many users administrator access
• Using shared administrator accounts
• Allowing unrestricted external sharing
• Creating Teams without owners
• Storing important files in individual OneDrive accounts
• Failing to remove former employee accounts
• Ignoring security alerts
• Assuming every licence includes the same protection
• Using unmanaged personal devices
• Not reviewing guest access
• Applying no retention policy
• Having no independent recovery plan
• Introducing Copilot before reviewing permissions

These issues should be identified through regular Microsoft 365 security and governance reviews.

Planning a Microsoft 365 Migration

Moving to Microsoft 365 should be treated as a structured project.

Before migration, the firm should assess:

• Existing email
• Shared drives
• Client files
• Case-management systems
• User accounts
• Distribution groups
• Shared mailboxes
• Applications
• Mobile devices
• Security controls
• Retention requirements
• Backup systems

The project should establish which information belongs in Exchange, Teams, SharePoint, OneDrive or a specialist legal application.

Simply moving every existing folder into the cloud may result in a confusing environment that is difficult to manage.

Testing should be completed before the old systems are removed.

Employees should also receive training covering the new file locations, sharing procedures and support process.

Microsoft 365 Requires Ongoing Management

Microsoft 365 is continually updated, and the way a firm uses it will change over time.

New employees join, suppliers gain access, Teams are created and information is shared externally.

Microsoft maintains a roadmap showing upcoming Microsoft 365 changes, while making clear that estimated release dates and planned features may change. (Microsoft)

The firm or its managed IT provider should therefore review:

• Security alerts
• Licence usage
• User accounts
• Guest users
• Administrator access
• Sharing links
• Device compliance
• Email protection
• Retention
• Backup results
• New Microsoft features

Microsoft 365 should not be configured once and then ignored.

How Hamilton Group Can Help

Hamilton Group helps law firms implement, secure and manage Microsoft 365.

We can help with:

• Microsoft 365 migrations
• Exchange Online
• Microsoft Teams
• SharePoint and OneDrive
• Multi-factor authentication
• Conditional Access
• Microsoft Intune
• Managed endpoint protection
• Microsoft Defender
• Email security
• DMARC, SPF and DKIM
• Sensitivity labels
• Data-loss prevention
• Microsoft Purview
• Microsoft 365 backups
• Licence reviews
• Copilot readiness
• User training
• Ongoing managed IT support

We can review your existing Microsoft 365 environment, identify potential security and permission gaps and create a practical improvement plan for your firm.

At Hamilton Group, we aim to make first contact on IT support requests within 15 minutes, helping legal professionals receive assistance quickly when a technical or security issue affects their work.

Call Hamilton Group today on 0330 043 0069 to discuss how Microsoft 365 can help your law firm work securely, collaborate effectively and protect confidential client information.

Microsoft 365 features and licensing can change. This article provides general information and should not be treated as legal, regulatory or data-protection advice.