When you use Copilot in Outlook Mobile with multiple Exchange accounts, the app must decide which account’s data to use for generating email summaries, drafts, and replies. Users often report that Copilot appears to ignore the active mailbox or pulls content from the wrong account. This behavior is not random it follows a strict selection rule based on the account order in Outlook settings. This article explains exactly how Copilot selects an Exchange account when multiple accounts are configured and what you can do to control which account Copilot uses.
The root cause is that Copilot in Outlook Mobile does not automatically detect the folder you are currently viewing. Instead, it defaults to the first Exchange account in the account list regardless of which mailbox you have open. This can cause confusion when you are reading email in a secondary account and Copilot generates responses using data from the primary account.
This article covers the selection algorithm, how to verify which account is active for Copilot, and how to change the default account order to match your workflow. It also explains the limitations Copilot has when accessing multiple Exchange mailboxes simultaneously.
Key Takeaways: Copilot Account Selection in Outlook Mobile
- Outlook Mobile account list order: Copilot uses the first Exchange account in the account list as its data source, not the currently open mailbox.
- Outlook Mobile > Settings > Accounts > Reorder: Drag accounts to change their priority. The top account becomes the default Copilot source.
- Copilot pane > Current account indicator: A small label at the top of the Copilot pane shows which account Copilot is using. Verify this before generating content.
Why Copilot Picks One Exchange Account Over Another
Outlook Mobile stores your Exchange accounts in a list. The order of this list is defined by the sequence in which you added the accounts or by manual reordering. When you open Copilot and request a summary or draft, the app scans the account list from top to bottom. It selects the first Exchange account it finds that has an active connection and a mailbox with data. This selection happens once when the Copilot pane opens and does not change if you switch folders or accounts while the pane remains open.
The behavior is by design. Copilot in Outlook Mobile does not have permission to merge data from multiple Exchange accounts in a single session. It must choose one account as its data source. The selection algorithm prioritizes the order in the account list over the currently viewed folder. This means that even if you are reading email in your work account, Copilot may use your personal account if it appears first in the list.
Microsoft has confirmed this behavior in official documentation. The company states that Copilot uses the primary account defined in the account list and that this setting cannot be overridden per email thread. The only way to change which account Copilot uses is to change the account order or to close and reopen the Copilot pane after switching to the desired account.
How to Check Which Account Copilot Is Using
Before you write a reply or ask for a summary, verify the active account in the Copilot pane.
- Open Outlook Mobile on your device
Launch the app and navigate to any folder in any mailbox. - Tap the Copilot icon at the bottom of the screen
The icon looks like a sparkle. This opens the Copilot pane. - Look at the top of the Copilot pane
You will see a small label that says Using account followed by the email address. This is the account Copilot will use for all requests in this session. - If the account is wrong, close the Copilot pane
Tap the X in the upper-left corner to close the pane. - Switch to the correct mailbox first
Open the account switcher by tapping your profile picture or the account icon. Select the account you want Copilot to use. - Reopen the Copilot pane
Tap the Copilot icon again. The label should now show the correct account.
If the label still shows the wrong account, the account order in Settings is overriding your folder selection. Continue to the next section to reorder your accounts.
How to Change the Default Account for Copilot
To permanently change which Exchange account Copilot uses, reorder the account list in Outlook Mobile settings.
- Open Outlook Mobile and tap your profile picture
This opens the account management screen. You will see a list of all accounts added to the app. - Tap the gear icon to open Settings
The Settings menu appears. - Tap Accounts
You see the full list of accounts with a Reorder option at the top. - Tap Reorder
Each account row gains a drag handle three horizontal lines on the right side. - Drag the account you want Copilot to use to the top of the list
Hold the drag handle and move the account up. Release when it is in the first position. - Tap Done in the upper-right corner
The new order is saved immediately. - Close and reopen the Copilot pane
The label should now show the account you moved to the top.
This change affects all Copilot features including summarize, draft, and coaching. It does not affect which account sends outgoing mail. The Send As account is still controlled by the folder you are viewing when you compose a new message.
Limitations and Edge Cases With Multiple Accounts
Copilot Cannot Access Data From More Than One Account Per Session
If you ask Copilot to find an email from your work account while Copilot is set to your personal account, the request will fail. Copilot only searches the mailbox of the account shown in the Using account label. To search a different account, you must close the pane, switch to that account, and reopen the pane.
Switching Accounts Mid-Session Does Not Update Copilot
If you switch to a different mailbox while the Copilot pane is still open, the Using account label does not update. Copilot continues to use the original account until you close and reopen the pane. This is the most common source of user confusion.
Copilot Does Not Support Shared Mailboxes in Outlook Mobile
If you have a shared Exchange mailbox added to your account list, Copilot will not use it as the default account even if you reorder it to the top. Shared mailboxes are excluded from Copilot data sources in Outlook Mobile. You must use a full Exchange account with a user license to use Copilot.
Copilot Ignores Non-Exchange Accounts
Accounts such as Gmail, Yahoo, or iCloud are skipped during the selection process. Copilot only considers Exchange Online or on-premises Exchange accounts. If your account list contains only one Exchange account and several non-Exchange accounts, Copilot will always use that single Exchange account.
Copilot Account Selection Behavior: Outlook Mobile vs Desktop
| Item | Outlook Mobile | Outlook Desktop |
|---|---|---|
| Account selection method | Uses first Exchange account in account list | Uses the folder currently open in the main window |
| Update when switching folders | Does not update. Must close and reopen Copilot pane | Updates automatically when you select a different mailbox in the folder pane |
| Manual override option | Reorder account list or reopen pane after switching mailbox | Switch folder in the folder pane |
| Shared mailbox support | Not supported | Supported with delegate access |
| Non-Exchange account handling | Skipped during selection | Skipped during selection |
Understanding these differences helps you avoid frustration when switching between devices. The desktop version is more flexible because it respects your current folder. The mobile version requires a deliberate workflow change to use Copilot with a secondary account.
Now you know exactly how Copilot in Outlook Mobile selects an Exchange account when you have multiple accounts configured. The key control is the account order in Settings. To use Copilot with a specific account, move that account to the top of the list. If you need to switch accounts temporarily, close the Copilot pane, switch your folder view, and reopen the pane. For advanced workflows, consider using the desktop version when you need to switch accounts frequently within the same session.