Weird SYNC HOLD appeared on Outlook Calendar

Dear Jeffrey,

Good day, and I appreciate the clear explanation of your concern. I'm truly sorry to hear that these "SYNC HOLD" calendar items are appearing and causing concerns with your calendar synchronization. I can only imagine how disruptive this must be, especially when your calendar is used for work scheduling and your busy/free availability needs to remain accurate.

As a forum moderator, I genuinely wish I could directly access your mailbox, Outlook profile, Exchange calendar logs, or connected sync services to confirm exactly what created these items. Unfortunately, my role here is limited to providing general guidance and troubleshooting steps that you can try from your side.

From your description and my research, this does not look like a normal Outlook calendar status label. Outlook and Exchange normally sync calendar events between Outlook and the Exchange server automatically, but "SYNC HOLD" is not a typical user-facing Exchange calendar state. Based on the wording and repeated pattern, these items may have been created by a third-party sync tool, calendar connector, automation flow, shared-calendar process, or booking/scheduling integration, rather than by Outlook itself.

Please try the following checks:

1.Outlook on the web

• Go to outlook.office.com
• Open the same calendar.
• Confirm whether the SYNC HOLD items also appear there.

2.Open one SYNC HOLD item

Open one of the affected items and check the following details:

• Organizer
• Created by / modified by, if visible
• Recurrence
• Calendar location
• Whether the item is a meeting, appointment, or copied event
• Whether there are any notes showing the source of the sync

3.Connected calendar / sync services

Since these look like generated placeholder events, please check whether you have any of the following connected to your account:

• Power Automate flows
• Calendar sync tools
• Google/iCloud calendar sync
• Bookings, Calendly, or scheduling tools
• Third-party Outlook add-ins
• Mobile calendar apps syncing the same account
• Shared calendar or delegate calendar sync

4.Test in Outlook Safe Mode

• Close Outlook.
• Press Windows + R.
• Run: outlook.exe /safe
• If the issue stops in Safe Mode, an Outlook add-in may be involved.

5.Contact technical support

If the issue persists, I would recommend reaching out to your IT administrator. For Exchange Online calendar issues, Microsoft provides Calendar Diagnostic Logs, which can help administrators investigate meeting and calendar actions such as deleted meetings, missing meetings, attendee changes, or calendar inconsistencies. The admin can investigate one affected calendar item and determine whether Exchange, Outlook, or another client/service created or modified it.

For references: 

Use Calendar diagnostic logs to resolve calendar issues - Exchange | Microsoft Learn

Analyze Calendar diagnostic logs for Exchange Online mailboxes - Exchange | Microsoft Learn

If you don't know who your IT administrator is, please refer to this article: How do I find my Microsoft 365 admin? - Microsoft Support 

Additionally, your IT administrator can submit a support ticket via the Microsoft 365 Admin Center on your behalf. This allows Microsoft support to review your account logs, provide live assistance, and investigate the issue thoroughly. For detailed instructions on how to get support, please refer to Get support - Microsoft 365 admin.

I hope this information helps clarify the situation and provides you with a clear path forward. Should you have any further questions or need additional assistance, please don't hesitate to reach out. I'm always happy to help. Wishing you a wonderful day ahead.

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