<div>
Could you delete Google calendar app, which also will delete all appointments. then re-synchronize with Samsung calendar app.<br />
<br />
You can refer the similar thread here: <a href="https://support.google.com/calendar/thread/494848?msgid=2398810" rel="ugc nofollow">https://support.google.com/calendar/thread/494848?msgid=2398810</a>
</div>


Could you delete Google calendar app, which also will delete all appointments. then re-synchronize with Samsung calendar app.

You can refer the similar thread here: https://support.google.com/calendar/thread/494848?msgid=2398810 [https://support.google.com/calendar/thread/494848?msgid=2398810]

<div>
<div class="content wysiwyg-content">
In outlook, not worries, but in both the Samsung and Google Calendar I get duplicates. &nbsp;I have unclicked all calendars and no matter which one I select I get exact duplicates for every event. &nbsp;I deleted outlook from phone, no difference. &nbsp;I have restarted. &nbsp;I have made sure that there is only one email account for the office 365 source calendar. &nbsp;<br />
<br />
In short, if I start with blank calendar and click anyone claendar, I get duplicate events.
</div>
</div>


In outlook, not worries, but in both the Samsung and Google Calendar I get duplicates.  I have unclicked all calendars and no matter which one I select I get exact duplicates for every event.  I deleted outlook from phone, no difference.  I have restarted.  I have made sure that there is only one email account for the office 365 source calendar.  

In short, if I start with blank calendar and click anyone claendar, I get duplicate events.

Note 9 Calendar shows Duplicates

Microsoft Office is an integrated suite of applications that includes Outlook, Word, Excel, Access, PowerPoint, Visio and InfoPath, along with a number of tools to assist in making the individual components work together. Coding within and between the projects is done in Visual Basic for Applications, known as VBA.

Microsoft Office

Google is an American multinational technology company specializing in Internet-related services and products that include online advertising technologies, search, cloud computing, software, and hardware.

Google

Microsoft Outlook is a personal information manager from Microsoft, available as a part of the Microsoft Office suite. Although often used mainly as an email application, it also includes a calendar, task manager, contact manager, note-taker, journal, and web browser.

Outlook

Office 365 is a group of software plus services subscriptions that provides productivity software and related services to its subscribers. Office 365 allows the use of Microsoft Office apps on Windows and OS X, provides storage space on Microsoft's cloud storage service OneDrive, and grants 60 Skype minutes per month. Office 365 includes e-mail and social networking services through hosted versions of Exchange Server, Skype for Business Server, SharePoint and Office Online, integration with Yammer, as well as access to the Office software. All of Office 365's components can be managed and configured through an online portal; users can be added manually, imported from a CSV file, or Office 365 can be set up for single sign-on with a local Active Directory using Active Directory Federation Services.