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Outlook.com mailbox not exposing custom folders to Microsoft Graph API

Richard Pierce 0 Reputation points
2026-04-02T12:42:54.5733333+00:00 
My Outlook.com mailbox is not exposing any custom folders to the Microsoft Graph API. 
Only the default folders (Inbox, Sent Items, Drafts, Junk, Deleted Items) are visible.

I have tested this thoroughly:
- Custom folders created in the Outlook desktop app do not appear.
- Custom folders created directly in Outlook.com (browser) do not appear.
- Even brand-new folders with a single email inside them (e.g., “Test Folder”, “Reindex Test”, “Index Reset”) are not visible.
- The folder structure appears correctly in the Outlook.com web interface, so the folders exist on the server.
- The issue is that the mailbox’s folder index is not being published to the API layer.

This is a known Outlook.com issue where the mailbox index becomes corrupted or stuck. 
I need the Outlook.com engineering team to run a **mailbox index rebuild** on my account.

Please escalate this to the Outlook.com backend support team.
Microsoft 365 and Office | Development | Other
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  1. Richard Pierce 0 Reputation points
    2026-04-17T09:53:27.3833333+00:00

    Hi Steven,

    Thanks for the reply. I am not calling Microsoft Graph directly. I am a normal Outlook.com user and the issue is that my mailbox is not publishing any of my custom folders to connected Microsoft services.

    To be clear:

    • My custom folders appear correctly in Outlook.com on the web.

    • My custom folders appear correctly in the Outlook desktop app.

    • But connected Microsoft services (including Copilot) can only see the default folders (Inbox, Sent Items, Drafts, Junk, Deleted Items).

    • Even brand‑new folders created directly in Outlook.com with a test email inside them do not appear to connected services.

    This is not an API coding issue. It is a mailbox indexing issue on the Outlook.com backend.

    Please escalate this to the Outlook.com engineering team for a mailbox index rebuild, as this is the known fix for Outlook.com accounts where custom folders are not being published to connected Microsoft services.

    Let me know if you need any further information.

  2. Steven-N 24,600 Reputation points Microsoft External Staff Moderator
    2026-04-02T13:37:50.4466667+00:00

    Hi Richard Pierce

    Thank you for reaching out to Microsoft Q&A forum

    Based on your description, I understand that your personal Outlook.com mailbox contains custom folders that are visible in Outlook.com on the web, but when you query Microsoft Graph, you only see the default folders (Inbox, Sent Items, Drafts, Junk Email, Deleted Items), and none of the user-created folders appear.

    However, in order to clarify detail of this concern then assist you better, could you give me the additional information below

    1. Which exact Microsoft Graph endpoints are you calling to enumerate folders, and are you traversing the hierarchy (for example, /me/mailFolders as well as /me/mailFolders/inbox/childFolders and deeper levels), rather than only listing the root’s immediate child folders?
    2. What authentication flow and permissions are you using for this personal Outlook.com mailbox (delegated vs app-only), and what Mail scopes are present in the access token?
    3. Do any of the folders fall under special conditions that affect enumeration, such as being hidden (and therefore requiring includeHiddenFolders=true), being nested under Inbox/subfolders, or coming from an IMAP/PST import history?

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