Exchange Connection Problems

How to Prevent Users from Deleting Shared Mailbox Messages in Microsoft 365

Elise Williams Oct 10, 2026 869 views

Question details

Determine the best methods to retain important messages, such as invoices, in a shared mailbox and prevent users from permanently deleting them.

How to Prevent Users from Deleting Shared Mailbox Messages

Product: Microsoft 365 Exchange Online
Device & OS: not provided
Scenario: An organization relies on a shared mailbox to receive critical business documents and needs to ensure these messages are preserved even if users attempt to delete them.
Observed behavior: Users with Full Access to the shared mailbox can delete emails, removing them from the active inbox view for all other mailbox members.

Before you start

Ensure you have Microsoft 365 administrator privileges, as modifying retention policies or Exchange mailbox permissions requires access to the Microsoft Purview compliance portal and Exchange admin center.

Solution 1Recommended

Configure a Microsoft 365 Retention Policy

A retention policy ensures that even if users delete emails from their view, the data is preserved in the background for a specified duration to meet compliance and recovery needs.

Applying a retention policy to a shared mailbox is the most robust way to preserve data. While it does not gray out the delete button for users, it guarantees that deleted items are securely retained in the Recoverable Items folder.

This allows administrators to retrieve 'deleted' messages via eDiscovery whenever necessary.

Access the Compliance Portal

Navigate to Retention Policies

Go to 'Data lifecycle management' > 'Microsoft 365', and then select the 'Retention policies' tab.

Create a New Policy

Click 'New retention policy', provide a descriptive name for the policy, and click Next.

Target the Shared Mailbox

Choose 'Exchange email' as the location. Click 'Edit' under the included column and specifically select the shared mailbox you want to protect.

Set Retention Settings

Define the retention period (e.g., 5 or 7 years) and specify that items should be retained even if users delete them. Save and apply the policy.

Configure a Microsoft 365 Retention Policy

User Interface Behavior: A retention policy operates on the backend. Users will still be able to move items to the Deleted Items folder, but the messages will remain preserved in the system.

Solution 2

Restrict Mailbox Permissions

If users only need to view emails but not reply or manage the inbox, restricting their permissions can prevent deletion altogether.

Free Microsoft Office alternative

Manage Your Exported Invoices and Documents Efficiently with WPS Office

While Microsoft 365 handles your complex email server retention rules, WPS Office offers a lightweight, free alternative for viewing, editing, and managing the actual invoice documents and spreadsheets received in your shared mailbox.

1. Download WPS Office: Visit the official WPS website to download and install the free WPS Office suite.
2. Save Attachments: Export your critical invoices or reports from the shared mailbox to your local storage.
3. Open and Edit Seamlessly: Launch WPS Writer, Spreadsheet, or PDF to effortlessly open, review, and organize your saved business documents.

Fully compatible with Microsoft Word, Excel, and PowerPoint formats.Lightweight and fast, opening heavy invoice PDFs and data spreadsheets instantly.Built-in PDF toolkit for easy editing, signing, and sharing of business documents.Free to use with a familiar, easy-to-navigate user interface, ensuring seamless migration.

Frequently Asked Questions

Can I completely block the delete button for users in an Exchange shared mailbox?

Exchange Online does not offer a native way to gray out or disable the delete button for users who have 'Full Access' permissions. The best workaround is to rely on retention policies to preserve data on the backend, or reduce user permissions to read-only.

Where do deleted shared mailbox emails go if a retention policy is active?

When a user deletes an email and clears it from the Deleted Items folder, it is moved to a hidden Recoverable Items folder. If a retention policy applies, the email remains there until the retention period expires, accessible only to administrators via eDiscovery.

Can I use Litigation Hold instead of a retention policy for shared mailboxes?

Yes, placing the shared mailbox on Litigation Hold will also preserve all deleted items indefinitely or for a specified duration. This serves a similar purpose to a retention policy and requires the appropriate Exchange Online Plan 2 or add-on licensing.

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