Microsoft 365 2025 Guide: Manage OneDrive Access, Inactive Mailboxes, and Compliance Searches

Advanced Microsoft 365 Data Management: Updated Guide for OneDrive Access, Inactive Mailboxes, and Content Searches (2025)

Microsoft continues to evolve its Microsoft 365 ecosystem to simplify data access, compliance, and retention for IT administrators. The latest 2025 updates enhance OneDrive file access management, introduce better inactive mailbox handling, and modernize Content Search and eDiscovery capabilities through Microsoft Purview. These updates help organizations meet regulatory requirements, maintain operational continuity, and enhance data governance.

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🔹 Granting Access to Another User’s OneDrive in Microsoft 365 (Updated 2025 Method)

Purpose

Providing OneDrive access to another user enables authorized individuals to retrieve, manage, or transfer important data during absences, transitions, or offboarding. The latest Microsoft 365 updates simplify this process by integrating access management directly into the Microsoft 365 Admin Center and Microsoft Purview Data Lifecycle Management tools.

Key Benefits:

• Ensures seamless access to files during staff transitions or leaves.
• Enables compliance with organizational data retention policies.
• Reduces dependency on manual PowerShell configurations.

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Configuration Steps (2025 Update)

Using Microsoft 365 Admin Center

1. Sign in to Microsoft 365 Admin Center as a Global or SharePoint Admin.
2. Navigate to Users → Active users.
3. Select the user whose OneDrive access needs to be delegated.
4. Under the OneDrive tab, select Manage Access → Create direct link to files.
5. You can now:
   • Copy the generated link for another user, or
   • Use Manage site permissions to assign direct access.

New in 2025: The OneDrive Access Delegation Wizard now includes a simplified interface to automatically grant temporary or time-limited access.

Using PowerShell (Updated Command Behavior)

# Connect to the SharePoint Online Admin Center
Connect-SPOService -Url https://contoso-admin.sharepoint.com

# Assign site collection admin rights to another user
Set-SPOUser -Site https://contoso-my.sharepoint.com/personal/user1_contoso_com `
-LoginName user2@contoso.com -IsSiteCollectionAdmin $true

You can now manage delegated access expiration via Microsoft Graph:

# Optional: Set an expiry date for delegated access
Update-MgSitePermission -SiteId <SiteID> -ExpirationDateTime "2025-12-31T23:59:59Z"

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Validation

• Check if the assigned user can access the target OneDrive via Microsoft 365 → OneDrive → Shared with you.
• Run permission verification with: Get-SPOUser -Site https://contoso-my.sharepoint.com/personal/user1_contoso_com
• Review and log access events in Microsoft Purview Audit Logs for compliance visibility.

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Best Practices

• Grant access to only trusted and essential personnel.
• Use temporary access links where possible to enhance data security.
• Monitor audit logs for OneDrive activity using Microsoft Purview.
• Remove delegated access promptly when no longer needed.

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🔹 Creating and Managing Inactive Mailboxes in Exchange Online (2025 Update)

Purpose

An Inactive Mailbox retains the data of a deleted user while blocking sign-in. Microsoft’s 2025 updates integrate inactive mailbox lifecycle management into Microsoft Purview Compliance Portal, making compliance operations more streamlined and discoverable.

Key Benefits:

• Preserves mailbox data even after user deletion.
• Enhances audit and legal discovery processes.
• No longer requires standalone eDiscovery configuration — now unified under Purview.

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Configuration Steps (Updated)

Pre-Deletion Requirement

Before deleting a user, apply a Retention Policy or Litigation Hold through Microsoft Purview → Data Lifecycle Management:

1. Navigate to Purview Portal → Data Lifecycle Management → Retention Policies.
2. Create a new policy → Apply to Exchange mailboxes.
3. Set retention duration (e.g., retain for 7 years).
4. Save and publish.

Once the user account is deleted, the mailbox transitions into Inactive Mailbox state automatically.

PowerShell Management

# Connect to Exchange Online
Connect-ExchangeOnline

# List inactive mailboxes
Get-Mailbox -InactiveMailboxOnly | Format-Table DisplayName,WhenSoftDeleted,ArchiveStatus

# Assign compliance access for eDiscovery
Add-MailboxPermission -Identity "InactiveUser@contoso.com" `
-User "complianceuser@contoso.com" -AccessRights FullAccess

New 2025 feature: Administrators can now restore inactive mailboxes directly from Purview with preservation of eDiscovery tags.

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Validation

• Confirm the mailbox appears under Inactive Mailboxes in the Exchange Admin Center (EAC).
• Verify compliance or legal teams can access content through Microsoft Purview eDiscovery (Premium).
• Attempt sign-in to confirm the mailbox remains inactive.

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Best Practices

• Apply retention holds before deletion to avoid permanent data loss.
• Restrict inactive mailbox access to compliance and security roles only.
• Audit inactive mailboxes quarterly for retention accuracy.
• Maintain written documentation for regulatory audits.

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🔹 Performing a Content Search in Microsoft Purview Compliance Center (2025 Workflow)

Purpose

The 2025 Microsoft Purview update enhances Content Search by integrating it into the eDiscovery (Standard) and eDiscovery (Premium) workflows. It allows comprehensive data discovery across Exchange, Teams, OneDrive, SharePoint, and Loop workspaces — now with contextual insights and AI-driven filters.

Key Benefits:

• AI-powered keyword suggestions and content classification.
• Unified management for cross-platform searches.
• Direct export to eDiscovery cases or audit logs.

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Configuration Steps (2025 Process)

Step 1: Assign Permissions

1. Sign in to the Microsoft Purview Portal.
2. Navigate to Permissions → Compliance roles → eDiscovery Manager.
3. Add compliance officers or admins as Content Search Managers.

Step 2: Create a New Search

1. Open Content Search → + New Search.
2. Enter name and description (e.g., Project Horizon Discovery).
3. Choose search locations:
   • Exchange Mailboxes
   • SharePoint Sites
   • OneDrive Accounts
   • Teams & Loop Workspaces
4. Apply filters using Keywords, Date Range, or File Types.
5. Save and run the search.
6. Review progress → Preview or Export Results in .pst or .csv format.

PowerShell (Modern Graph Integration)

# Connect to Purview via PowerShell
Connect-IPPSSession

# Create a search with conditions
New-ComplianceSearch -Name "ProjectHorizonSearch" `
-ExchangeLocation All -ContentMatchQuery 'subject:"Horizon Project" AND sent>=01/01/2025'

# Run the search
Start-ComplianceSearch -Identity "ProjectHorizonSearch"

# Get search results
Get-ComplianceSearch -Identity "ProjectHorizonSearch"

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Validation

• Verify that the search completes successfully in Purview.
• Preview and confirm relevant matches.
• Validate access controls — only eDiscovery Managers can view/export data.
• Document search queries and export logs for compliance review.

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Best Practices

• Use specific keywords to reduce search size and improve precision.
• Schedule recurring searches for ongoing investigations.
• Retain search logs under Purview Audit → Search Activity.
• Limit eDiscovery roles to compliance-approved personnel.

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🧩 Conclusion

The Microsoft 365 platform now provides enhanced, unified tools for secure data management:

• OneDrive Access Management: Streamlined with temporary access controls and Microsoft Graph support.
• Inactive Mailbox Retention: Fully integrated with Microsoft Purview lifecycle management.
• AI-Enhanced Content Search: Smarter and faster data discovery across Microsoft 365 apps.

These updates empower IT administrators and compliance officers to balance productivity, security, and regulatory compliance with more precision and automation than ever before.

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