A former employee can still access a SharePoint folder months after leaving. A finance team may have a mailbox delegate no one remembers approving. A well-meaning user can share sensitive files with external guests. These are common reasons to audit Microsoft 365 permissions before an incident exposes the gap.

For growing organizations, permission reviews are not just an IT cleanup task. They are a practical control for protecting customer data, financial records, employee information, and the workflows that keep the business operating. The goal is not to restrict every user. It is to make sure access is intentional, appropriate, and traceable.

Why Microsoft 365 permissions become difficult to manage

Microsoft 365 makes collaboration easy, which is valuable until access grows faster than oversight. Every new employee, project team, shared mailbox, Teams channel, SharePoint site, contractor, and software integration introduces another access decision.

Over time, permissions often accumulate through normal business activity. A manager grants access to keep a project moving. An employee changes roles but retains access from the prior position. A department creates a Team outside the standard provisioning process. None of these actions are necessarily careless, but together they create excessive access and unclear ownership.

The risk is not limited to malicious activity. Excessive permissions can cause accidental file deletion, unintended external sharing, unauthorized changes to business records, and confusion during an employee departure. In regulated industries such as healthcare and financial services, poor access governance can also complicate audit readiness and contractual obligations.

A useful permission audit answers three business questions: who has access, what can they do, and does the access still support a current business need?

Start an audit Microsoft 365 permissions process with scope

Trying to review every setting at once usually produces a long report and few decisions. Start by defining the systems and access types that create the highest operational or security risk. For most organizations, the first review should include:

• Microsoft 365 administrator roles and privileged accounts
• User accounts, inactive accounts, and accounts without strong sign-in controls
• Shared mailboxes, mailbox delegation, and forwarding rules
• Microsoft Teams, Microsoft 365 Groups, and SharePoint site membership
• OneDrive sharing, external guests, and anonymous sharing links
• Enterprise applications, OAuth consent, and service accounts

Prioritize systems that hold sensitive information or support critical processes. Finance, HR, executive communications, customer records, healthcare information, and operational documentation deserve early attention. A construction firm may prioritize project sites and bid folders. A professional services organization may begin with client workspaces and shared mailboxes.

Define who can make access decisions before collecting evidence. IT can identify where permissions exist, but department leaders are usually better positioned to confirm whether a user still needs access. This separation matters. Technical visibility without business ownership leads to guesswork, while business approval without technical validation can overlook hidden access paths.

Review privileged access first

Administrator permissions deserve the most disciplined review because they can change security settings, create accounts, read data, or disrupt operations. Review Microsoft 365 global administrators, Exchange administrators, SharePoint administrators, Teams administrators, Intune administrators, security administrators, and any custom privileged roles.

A common mistake is assigning Global Administrator rights for convenience. Global Administrator should be limited to a small number of accountable individuals and used only when the task requires it. Day-to-day support work should use narrower roles. This reduces the impact if an account is compromised or an administrative action is made in error.

Also review whether each privileged account has multifactor authentication, conditional access protections, a documented owner, and a legitimate operating purpose. Shared administrator credentials should be eliminated. Administrative actions should be attributable to an individual, even when an outsourced IT provider supports the environment.

For higher-risk environments, use separate administrative accounts rather than giving daily email accounts persistent elevated privileges. This adds a small amount of administrative overhead, but it meaningfully reduces exposure from phishing and session theft.

Check service accounts and application access

Service accounts and connected applications are easy to overlook because they may not belong to an active employee. They can support backups, line-of-business integrations, reporting tools, scanners, or automated workflows. Each should have a named business owner, a documented purpose, and only the permissions needed to perform its function.

Review enterprise applications that have been granted access to Microsoft 365 data. Pay close attention to applications with permissions to read mail, access files, manage users, or operate without a signed-in user. Remove abandoned integrations and investigate unfamiliar applications before simply disabling them. Some may support critical workflows, so a controlled change process is essential.

Examine collaboration access where data is shared

Teams, SharePoint, and OneDrive create the most permission sprawl in many organizations. A single user may receive access directly, through a Microsoft 365 Group, through a Team, or through a SharePoint permission group. That makes it possible for access to remain after someone is removed from one location.

Review high-value Teams and SharePoint sites by confirming the business owner, members, visitors, external guests, and sharing settings. Every site should have an accountable owner who can validate membership and make timely decisions when users change roles or leave the business.

External sharing requires a balanced approach. Disabling it entirely may slow work with clients, vendors, subcontractors, and advisors. Allowing broad anonymous sharing creates unnecessary exposure. A practical policy often permits authenticated guest access for approved collaboration while limiting anonymous links, setting expiration dates, and reviewing guest accounts on a defined schedule.

OneDrive deserves separate attention because users can share individual folders and files outside the structure of a department site. Check whether sensitive files are broadly shared, whether external links are still active, and whether departed users’ OneDrive content has been transferred or retained according to policy.

Validate identity lifecycle controls

The strongest permission review is weakened if user accounts are not managed consistently from hire through departure. Access should follow a documented lifecycle: request, approval, provisioning, review, change, and removal.

Compare active Microsoft 365 accounts against an authoritative employee and contractor list. Investigate accounts belonging to former employees, temporary workers, or users who have not signed in for an extended period. Inactive accounts are not always unnecessary. Some support shared processes or archive requirements. They should, however, have a documented owner and a reason to remain enabled.

Role changes need the same attention as offboarding. When an employee moves from operations to finance, or from one client team to another, old access is often retained because no one is assigned to remove it. A manager-approved access review at role change prevents permissions from becoming permanent by default.

Document decisions, not just findings

An audit report that lists hundreds of permissions is less useful than a decision record that shows what changed and why. For each significant finding, document the system, the user or group, the level of access, the business owner, the decision, and the completion date.

Classify findings by urgency. A former employee with an active account, an unknown Global Administrator, or a public link to sensitive data should be addressed immediately. An overpopulated project site may require a planned review with the department owner. This distinction helps leadership focus resources where they reduce risk fastest.

Avoid removing access in bulk without validation. Permission cleanup can interrupt payroll processing, customer service, project delivery, or a critical application integration. Where possible, notify owners, test changes, and maintain a clear rollback path for business-critical systems.

Make permission reviews repeatable

Microsoft 365 permissions change constantly, so a one-time review offers only temporary assurance. Establish a review cadence based on risk. Privileged roles, guest access, and high-sensitivity sites may need monthly or quarterly review. Standard department memberships may be reviewed quarterly or semiannually, depending on workforce turnover and the sensitivity of the data.

The process should combine automated reporting with human accountability. Reports can identify unusual administrator assignments, dormant accounts, external sharing, and stale guest users. Managers and data owners must still confirm whether access supports current work. Automation provides visibility; accountable decisions provide control.

A managed IT partner can help centralize this work by maintaining documentation, monitoring identity changes, supporting onboarding and offboarding, and escalating exceptions that require leadership input. The value is not merely a cleaner tenant. It is a more reliable operating model where access decisions are visible, timely, and aligned with the way the business actually works.

Permission governance works best when it becomes part of ordinary business discipline: grant access deliberately, review it regularly, and remove it promptly when the need ends.