Importing CSV into shared calendar does not update on shared users calendar

[teo_1435]

Our company has been using shared calendar actively and has been importing csv to share calendar with other employees. However the shared calendar isn't updated on the shared user side, although it is being updated on the local user calendar only. This issue does not occur if you are manually updating the calendar. There was no issues all along with the method we use to do the importing and seeing the updated version on of the calendar until recently.... 

[#2]

How are you doing the import? Generally speaking, you'd need the Shared mailbox to be added as additional account in Outlook for this to work as expected.

[#3]

@Vasil Michev The accounts added to the shared calendar is part of the organisation domain. The import is done through the import export function of outlook. The synchronisation has no issues when the appointments are being manually updated, but only the imported items are not synchronised on the users accounts which the calendar is being shared with. 

[#4]

Right, but how is the shared calendar (mailbox) being accessed in Outlook. Many functionalities will only function properly when you have it added as additional account (via File > Add account), and for that you need to have Full access permissions (or the credentials). Other than that, check whether after the import you can see the items via the webmail/OWA, this will give you a clue whether it's some sort of a sync issue.

[#5]

Did you ever find a solution to this? We are facing the same issue. After importing the appts, if you double click to edit them and then save, they update across all users, so this seems to be some kind of import bug. TIA

[#6]

@teo_1435 
@Vasil Michev 

It seems to me that this is a bug in the CSV import function, as I found a (poor) work-around:

1. Import the CSV file.
2. Export the new appointments that won’t update to a PST file format (you can choose to only export a certain date range to make it faster).
3. Import the PST file back to the calendar, choosing the option to “replace duplicate items”.

The calendar then updates across all shares.

Given that exporting and re-importing from a PST works, this is not a setup or permissions issue, it must be a bug in the CSV import function.

[#7]

Just in case anyone else comes across this, also note that the import function (at least in 

Outlook® for Microsoft 365 MSO (Version 2311 Build 16.0.17029.20028) 64-bit) is picky about the exact encoding of the CSV file too. Saving from Excel in CSV (MS-DOS) format works, some of the others don't.

I created an empty PST file, imported the calendar entries to that, then using View / List View, it's easy to select all the events and move them to the shared calendar.