Outlook for Mac stops synching with Google Calendar

Tony Wilkinson 5 Reputation points
2026-08-28T07:51:24.52+00:00

My work uses google workspace with gmail and calendar. I use Outlook for Mac and Outlook for iPhone as my primary clients to access both services. This has worked well until recently. In the past month the synchronisation breaks down on a regular basis. It has now got to the point where it is happening almost daily. The synchronisation between outlook and gmail is working fine, but the synchronisation with Google Calendar stops working, such that new appointments created in Outlook do not show up in google Calendar, and changes in Google calendar are not reflected in outlook. The same behaviour happens with both legacy and current outlook for Mac

It appears that this is related to the authentication between Outlook and google. If I try to fix the connection by "resetting" the account in outlook then there is no change. I have to delete the account from within Outlook, then re-add it, which forces a re-creation of the access on the google side. This then works for a period of time but usually fails again within a day or two, requiring me to delete the account and synch all over again.

Can you please tell me why this connection keeps breaking and how to fix it without having to reset every day

thanks!

Outlook | Web | Outlook on the web for business | Calendar
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  1. AI answer

    2026-08-28T07:51:42.8766667+00:00

    What is supported from the documented issues is:

    1. Make sure the Google account is added as a Google account, not as IMAP. IMAP syncs mail only, not calendar or contacts. If meetings are not syncing, the account must be connected using the Google option.
    2. If the problem is connection-related, verify the Google-side settings required for Outlook:
      • In Gmail, enable IMAP: Settings > Forwarding and POP/IMAP > Enable IMAP > Save Changes.
      • In Gmail, make sure required folders are set to Show in IMAP: Settings > Labels > enable Show in IMAP for Inbox, Sent Mail, Trash, and All Mail.
      • After changing settings, refresh Outlook. Sync refresh can take up to 15 minutes. In Outlook for macOS, select Sync on the ribbon.
    3. For Google Calendar meeting responses to work correctly in Outlook, in Google Calendar web app set Settings > General > Automatically add invitations to my calendar to either of the Yes options.
    4. Some Google calendar behavior in Outlook for Mac is a known limitation, not a fixable local issue:
      • Attachments in events aren’t supported.
      • Deleting a meeting sends a response to the organizer even if Outlook says otherwise.
      • Shared Google calendars appear automatically in the left pane; Open Shared Calendar does not work for Google calendars.
      • There is currently a 20-calendar limit for calendars shared with the account.
    5. If the account was removed from Outlook for Mac using Sign Out On All devices, adding the same Google account back may take up to 4 hours.

    The provided material does not document a known root cause for a daily Google Calendar authentication break specifically affecting both legacy and current Outlook for Mac, and it does not provide a permanent self-service fix beyond confirming the account is connected as Google and verifying the required Gmail/Google Calendar settings above.

    References:

    AI-generated content may be incorrect. Read our transparency notes for more information.

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  2. Ana Le 2,345 Reputation points Independent Advisor
    2026-08-28T08:15:13.15+00:00

    Hi,

    As the forum’s AI recommended, please confirm that the account was added using the Google option rather than as an IMAP account. Microsoft documents that an IMAP connection supports mail only, while a Google connection can synchronize mail, calendar, and contacts: Sync account in Outlook for Mac to Microsoft Cloud⁠.

    However, because Google Calendar previously synchronized and temporarily works again after the account is re-added, the account type alone does not explain why synchronization stops after one or two days.

    The Gmail IMAP and folder-label settings mentioned earlier apply primarily to email synchronization. Since Gmail mail continues to synchronize normally, those settings are not aimed at this calendar-only issue. Likewise, the “Automatically add invitations” setting affects meeting invitations and responses, rather than ordinary appointments failing to synchronize in both directions.

    When the issue next occurs, please avoid removing the account immediately. Instead:

    1. Create one test event directly in the primary calendar at Google Calendar on the web.
    2. Create a different test event in Outlook for Mac, ensuring that the same primary Google calendar is selected.
    3. Select Sync on the Outlook ribbon and allow up to 15 minutes.
    4. At the same time, check both test events in Outlook for iPhone.

    Please then confirm:

    • Whether Outlook for iPhone also stops syncing at the same time, or only Outlook for Mac.
    • The Outlook for Mac version and build under Outlook > About Outlook, and the macOS version.
    • Whether the primary calendar, shared calendars, or both are affected.
    • Whether Outlook displays an exact error or warning.
    • Whether any other users in the same Google Workspace organization are experiencing this.

    Microsoft currently has a separate intermittent synchronization issue under investigation for Outlook for Mac and Outlook Mobile. However, the documented issue displays specific messages such as “We’re having trouble syncing the mailbox” or “Add account again.” It should not be treated as the same issue unless one of those messages appears: Outlook for Mac and Outlook Mobile intermittently stop syncing⁠.

    If Outlook for iPhone continues syncing while only the Mac fails, report the issue from Outlook for Mac under Help > Contact Support while the failure is still active: Contact support within Outlook for Mac⁠.

    If both Mac and iPhone stop syncing while Google Calendar on the web remains correct, the Google Workspace administrator should review the affected account under:

    • Security > Access and data control > API controls > Manage App Access
    • Reporting > Audit and investigation > OAuth log events

    The administrator should check for blocked, denied, or revoked Calendar access around the time synchronization stopped, without changing the organization’s access policy unless the review identifies an issue. See Google’s documentation: Control which apps access Google Workspace data⁠(This is a non-Microsoft website. The page appears to be providing accurate, safe information. Watch out for ads on the site that may advertise products frequently classified as a PUP (Potentially Unwanted Products). Thoroughly research any product advertised on the site before you decide to download and install it.)

    Until this is resolved, please create important appointments directly in Google Calendar on the web. Resetting or removing the account can remove locally created items that have not yet synchronized to the server.

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