How do I open my mailbox in Outlook 365?

Opening your mailbox in Outlook 365, whether it's your primary account or another mailbox you have access to, is a straightforward process. Your own mailbox is typically accessible immediately after signing in, while opening another shared or delegated mailbox involves a few extra steps.

## Accessing Your Primary Mailbox

To open *your own* primary mailbox in Outlook 365, you generally just need to sign in to the service.

1.  **Navigate to Outlook on the web:** Go to the [Outlook website](https://outlook.office.com).
2.  **Sign In:** Enter your Microsoft 365 email address and password.

Once you successfully sign in, your primary mailbox, containing your Inbox, Sent Items, and other folders, will be displayed by default.

## Opening Another Mailbox (Shared or Delegated)

If you have permission to access another user's mailbox, a shared mailbox, or a resource mailbox, you can open it from within your own Outlook on the web session.

Based on the provided reference, here's how to open another mailbox:

1.  **Sign in to your account in Outlook on the web.** (Ensure you are already logged into your own mailbox).
2.  **On the Outlook on the web navigation bar, click your name.** Your name is typically located in the upper right corner of the screen.
3.  **A list appears.** This dropdown list contains various options related to your account.
4.  **Click Open another mailbox.** This option will prompt you to enter the email address of the mailbox you wish to open.

After clicking "Open another mailbox," you will be asked to type the email address of the mailbox you want to access. Once you enter the address and confirm, the other mailbox will open in a separate browser tab or window, allowing you to view its contents.

### Steps at a Glance

| Step                            | Action                                      | Location                 |
| :------------------------------ | :------------------------------------------ | :----------------------- |
| 1. (Prerequisite)               | Sign in to your own Outlook account         | Outlook on the web       |
| 2. Click your name              | Select your profile name                    | Navigation Bar (top-right) |
| 3. A list appears               | Observe the dropdown menu                   | Below your name          |
| 4. Click "Open another mailbox" | Choose the option to access another account | From the list that appeared |

This process is specifically for opening mailboxes you have been granted permissions to access, such as shared mailboxes (e.g., [email protected]) or another colleague's mailbox if they have delegated access to you.

By following these steps, you can easily access both your primary Outlook 365 mailbox upon signing in and any other mailboxes you manage using the "Open another mailbox" feature in Outlook on the web.