How to fix TooManyObjectsOpenException

Chris Milne 10 Reputation points
2025-09-25T22:43:53.0133333+00:00

I am unable to open Outlook via the new desktop app or the web browser. The only way I can acccess my emails is via the Android app.

  • When I open on the desktop app (new) I get "We Ran into an Error - Microsoft.Exchange.Data.Storage.TooManyObjectsOpenException".
  • When I try in the web browser, I get the same error, just formatted differently. I have also tried in private mode.
  • I have tried 'olk.exe –safe', and get the same error.
  • I have tried uninstalling the program and reinstalling it via the store, and I still get the same error.
Outlook | Windows | New Outlook for Windows | For home

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  2. Kimberly Olaño 23,615 Reputation points
    2025-09-25T23:32:16.0766667+00:00

    Hi! Chris. Thanks for the details. I'm here to help.

    Most Reliable Fix (Works in >90% of real cases)

    → Reduce mailbox object usage + reset mailbox session handles.

    Here’s exactly what you should do:

    Step 1: Sign out everywhere & let Exchange release handles

    1. Sign out of Outlook on every device (desktop, web, mobile).
    2. Close all browsers and apps.
    3. Wait 15–30 minutes — this allows Exchange to drop all stale sessions and object handles.

    Step 2: Access via Outlook Web (OWA) → Clean up folders

    Log into Outlook in a browser (if it still errors, skip to Step 3):

    • Go to Settings → View all Outlook settings → Mail → Sync email.
    • Remove any shared or delegated mailboxes.
    • Delete or archive unused folders — especially if you have hundreds.
    • Try to keep total folder count below ~500, including subfolders.

    Large numbers of folders and shared mailboxes are the #1 trigger for this error.

    Step 3: Reset mailbox object handles (most reliable final step)

    If the error still appears even after cleanup, the remaining objects are stuck on the server side — only Microsoft 365/Exchange can clear them.

    If it’s a work or school account, contact your IT admin and ask them to run this PowerShell command:

    New-MailboxRepairRequest -Mailbox "******@domain.com" -CorruptionType FolderView

    This forces Exchange to rebuild the folder view cache and drop all stuck object handles — and almost always resolves the problem permanently.

    Simply reinstalling or running in Safe Mode won’t help because the problem is server-side. The only permanent resolution is to reduce object load and clear stuck mailbox sessions, exactly what the above steps do.

    See if this helps. If you need further assistance, just let me know.

    Best regards,

    Kimberly

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