Outlook duplicates internet calendar.

Copper Contributor

Hello experts :),
Someone in my company has an issue with internet calendars. He subscribed to his google agenda and the calendar appears in the "other calendar" section. So it seems to be good.

But after a while, there are "copies" of his calendar. CalendarName(1), CalendarName(2), ... (5) for example. It is like if Outlook duplicates calendar instead of overwriting the changes in the calendar.


He tried to delete them but after some time they reappears. Where does it come from? Duplicate option, sync issue ? 


13 Replies

@kiwivert Hello, are you able to go into the Calendar section of Outlook and tried deleting them? It also could be that he had maybe set up an online sync of Google Calendar. I would check all Calendar settings. In the mean time, follow this link for some help: https://support.office.com/en-us/article/Delete-a-calendar-9BA1364C-BDB0-41BE-8F66-EAF96698D021

 Hello @firefistmango  yes he can delete the internet calendars but after a while they reappears. So I would like to know what is the cause of that.


It could be bad PST file at that point. Also, is this a shared calendar?


He told me he has already :

deleted all Outlook data files,

deleted his Outlook profile,

subscribed to his calendar instead of added it. 


He told me he use Outlook on his laptop and on his phone. I wonder if it can be a part of the issue.

@kiwivert That could be it, as long as the file is originating somewhere, that is probably causing the issue.

@kiwivert I've been struggling with this for a while too - did you ever find a solution to it? The previous responses seemed more like wild guesses...




@Jonas Rapp No I didn't find a solution. I am still searching. Maybe it is just a sync problem between google calendar and outlook calendar or a dummy thing like this but I can find what is is exactly.

I have the same problem: repeated calls of a webcal - calender with c# (OpenSharedFolder(webCalString)  ) creates over and over new instances of the subscribed calender in outlook.exe. Details an a code example can be found here:   https://developercommunity.visualstudio.com/t/c-microsoftofficeinteropoutlook-opensharedfolderwe/153...

The Microsoft Visual Studio Team says it will be an Office problem. I still look for a solution. Any idea would be mostly welcomed!

I have had the same issue for about 3 years and still no solution - Ii delete multiple internet calendars, pst files, internet calendar folders, etc.  every day or so. I have had my profile rebuilt etc. These only appear on my desktop version of outlook (occured with both 2016 and my current 2019), not the microsoft 365 online version. Hope to hear of a solution one day....

@mel_jay I have just installed Office 365, the problem persists with Outlook 365.


Not sure how this solves anyone's problems as I have the same issue Numerous duplicated Internet calendars myself <1% of the people that need this fix are going to write C# code to fix this...


I myself literally deleted all the internet calendar subscriptions - default.pst files to try and fix this and once I restart Outlook upon deleting the Internet Calendar PST file and I subscribe to one of my internet Google Calendars it STILL somehow finds the older versions of the calendar that were supposed to have been deleted.  I even cleared out the entire Outlook Cache and it still comes back.  I think Microsoft doesn't care about this because it primarily only affects people who are using Google Calendars.  Utterly ridiculous that when you select 'Delete' it doesn't actually delete the instance that is stored somewhere.  How difficult is this to get correct????


I have spent days of my life trying to fix this stupid thing...