OUTLOOK HAS STOPPED WORKING

Bad Hobbit 0 Reputation points
2026-09-16T11:01:49.5033333+00:00

Like the Artemis astronauts, I have 2 copies of Outlook and NEITHER of them work. Outlook 'Classic' now exhibits AT LEAST the following faults (I'm sure there are others):

It refuses to send emails from my MAIN Gmail account. Sent items remain in the Outbox and are NEVER sent.

The mailbox refreshes when I open Outlook - but then not again until I shut down and reopen in

It HANGS after a variable amount of time. Though 'thumbnail' windows appear when I mouse-over the Outlook icon on the taskbar, clicking the Mail or Calendar thumbnails fails to open them. The only recourse is to END TASK (Close Window won't work) and start again.

Appointments on the calendar, when deleted or moved, do no show a successful result unless I switch to a different calendar and then switch back.

All of this worked fine until a few months ago. Now, every time you update, I get MORE BUGS. WHAT ARE YOU DOING? Does the term 'regression testing' mean nothing to you?

Outlook | Windows | Classic Outlook for Windows | For home
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  1. AI answer

    2026-09-16T11:02:11.52+00:00

    For classic Outlook for Windows, the supported first troubleshooting path is:

    1. Check for a hidden dialog box.
      • Press Alt+Tab and look for any Outlook confirmation window.
      • If a dialog is open, Outlook can appear frozen until that prompt is answered.
    2. Check whether Outlook is still processing a large background task.
      • Look at the status bar at the bottom of Outlook.
      • If Outlook is moving or deleting many messages, auto-archiving, or handling a large attachment, wait a few minutes.
    3. Install the latest Windows and Microsoft 365/Office updates.
      • Outlook works best when fully updated.
      • If this started after recent updates, there is also context showing some January 2026 Outlook issues were tied to specific Windows updates, and later updates resolved some cases.
    4. Repair Office.
      • Close all Microsoft 365 apps.
      • Open Control Panel > Programs and Features.
      • Right-click Microsoft Office 2016 and select Change.
      • Run the repair. This can take time.
    5. Start classic Outlook in safe mode.
      • Close Outlook.
      • Press the Windows key, type outlook.exe /safe, and press Enter.
      • If Outlook works in safe mode, an add-in or profile issue is likely involved.
    6. If sending still fails, repair the Outlook program and then repair the Outlook profile.
      • The documented send/receive troubleshooting path includes both Repair your classic Outlook program and Repair your classic Outlook profile.
    7. If mail is still stuck in Outbox, run the Inbox Repair Tool if the account uses a .pst file.
      • This is specifically documented for classic Outlook data-file issues.
    8. If Outlook becomes unresponsive and will not reopen cleanly, end it in Task Manager and reopen it.
      • This is documented for Outlook not responding.

    For the specific “stuck at Processing” behavior:

    • Close Outlook.
    • Start it with Outlook.exe /safe.
    • Close it again.
    • Reopen it normally.

    A known issue in the context also shows classic Outlook hanging when using the Copy shortcut, with a documented Click-to-Run update command. Warning: this requires an elevated Command Prompt and changes the installed Office build, so it should be used carefully and only for that specific copy-shortcut hang scenario:

    cd %programfiles%\Common Files\Microsoft Shared\ClickToRun
officec2rclient.exe /update user updatetoversion=16.0.17928.20156
    AI-generated content may be incorrect. Read our transparency notes for more information.

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  2. Hendrix-V 19,030 Reputation points Microsoft External Staff Moderator
    2026-09-17T01:48:12.4866667+00:00

    Hi Bad Hobbit,

    Based on the symptoms you've described, this may point to an Outlook profile or account synchronization issue rather than a single isolated problem.

    Here are some targeted checks that may help narrow it down:

    1, Create a new Outlook profile

    • Open Control Panel > Mail > Show Profiles
    • Select Add
    • Configure your accounts in the new profile
    • Set it as the default profile and test

    2, Check whether the issue is limited to the Gmail account

    • Try sending an email from another configured account (if available)
    • If only Gmail is affected, remove and re-add the Gmail account in Outlook

    3, Test Outlook without loading your normal Windows profile

    • Create a temporary local Windows user account
    • Open Outlook and add your account
    • Check whether the same freezing and synchronization issues occur

    If the behavior continues after testing with a new Outlook profile, please share your Outlook build number and whether the issue occurs with all accounts or only Gmail. That information can help determine whether this is profile-specific, account-specific, or related to the Outlook installation itself.

    Let me know if you need further assistance, feel free to ask me by clicking "Add Comment" or "Add Answer" if you cannot add comment so your response will be visible. Thanks for your effort.

    Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

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