How to Open Another Person’s Mailbox in Outlook on the web
Accessing another person’s mailbox in Outlook on the web allows authorised users to view and manage emails for shared inboxes, delegated accounts, or team mailboxes. This is commonly used for executive assistants, reception teams, finance departments, or staff managing shared communications. This guide explains how to open another mailbox, use it efficiently, and troubleshoot common access issues.
Mailbox Access Instructions
Method 1: Open Another Mailbox in a New Tab (Beginner Friendly)
Step 1: Sign in to Outlook on the Web
Open your web browser and sign in with your Microsoft 365 work or school account.
Step 2: Open Your Profile Menu
In the top-right corner, click your profile picture or initials.
Step 3: Select Open Another Mailbox
Choose Open another mailbox from the menu.
Step 4: Enter the Mailbox Name or Email Address
Type the full email address or name of the mailbox you have permission to access.
Step 5: Select the Mailbox
Choose the correct result, then click Open.
Step 6: Use the Mailbox
The mailbox will open in a new browser tab where you can read emails, move messages, manage folders, and send mail depending on your permissions.
Method 2: Add the Mailbox to Your Folder List
Step 1: Open the Folder Pane
In the left-hand folder pane, right-click Folders or your mailbox name.
Step 2: Add the Shared Mailbox
Select Add shared folder or mailbox.
Step 3: Enter the Mailbox Email Address
Type the full email address of the mailbox you need to access.
Step 4: Click Add
Click Add to add the mailbox to your folder list.
Step 5: Access the Mailbox
The mailbox will appear in your folder list for quick access.
Mailbox Access Best Practices
- Pin the mailbox tab in your browser if you use it daily.
- Use browser profiles to manage separate work environments.
- Check mailbox rules and folders if emails seem to be missing.
- Use search filters inside the shared mailbox to quickly find messages.
- Confirm sending rights if you need to send from the mailbox.
Fix Mailbox Access Issues
Beginner Troubleshooting
- Check Your Permissions
Make sure your Microsoft 365 administrator has granted you access. - Verify the Mailbox Address
Enter the correct full email address of the mailbox. - Sign Out and Sign Back In
If access was recently granted, signing in again may refresh permissions. - Refresh the Browser
Reload the page or reopen Outlook on the web.
Advanced Troubleshooting
- Clear Browser Cache and Cookies
Old browser data can cause loading or sign-in issues. - Try Another Browser or Private Window
Use an incognito/private session to test if browser extensions or saved sessions are causing the issue. - Allow Time for Permissions to Sync
New mailbox permissions may take time to update across Microsoft 365 services. - Check Send As or Send on Behalf Permissions
If you can open the mailbox but cannot send messages, separate sending permissions may be required. - Review Mailbox Size or Quota Issues
If the mailbox is slow or not updating, storage limits may need to be checked by your admin.
Important Mailbox Access Notes
- You can only access another mailbox if permission has been granted to your account.
- Some users may have read-only access, while others can send, delete, or manage folders.
- Any changes made inside the mailbox affect the live mailbox for all authorised users.
- If multi-factor authentication is enabled, complete all sign-in prompts first.
- Shared mailboxes and user mailboxes may behave slightly differently depending on permissions.
- Always follow your company’s privacy and security policies when accessing another user’s mailbox.
Mailbox Access FAQs
Why can’t I open another person’s mailbox?
You may not have the required permissions, or the mailbox address may be incorrect.
Why can I open the mailbox but not send emails from it?
You may need separate Send As or Send on Behalf permissions.
How long does it take for new permissions to work?
Permission changes can take some time to sync across Microsoft 365 services.
What should I do if none of these steps work?
Contact swazzy Support or your Microsoft 365 administrator for further assistance.
Mailbox Access Complete
Opening another person’s mailbox in Outlook on the web helps teams manage shared communication, delegated inboxes, and business email workflows more efficiently. By following the steps above, most access issues can be resolved quickly. If you continue to experience problems, contact your Microsoft 365 administrator or Swazzy Support for further help.
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