Graph API /createImportSession request

val19680507 1 Reputation point
2026-09-15T13:16:31.1633333+00:00

Hi All,

I use Graph API /createImportSession request and then the returned "importUrl" to replace EWS functionality <m:UploadItems>.

It works for messages and contacts but not for events.

I.e. I can read events with /exportItems but can't upload them with /createImportSession and then "importUrl". It returns unknown error.

So question - is such behavior correct and upload functionality is not implemented in Graph API for events or it's some problem on my side? If so, what can it be?

Microsoft Security | Microsoft Graph
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  1. Anthony Porter 310 Reputation points
    2026-09-16T23:06:49.53+00:00

    createImportSession supports importing Outlook items such as messages and contacts, but calendar events are not currently supported through the same import workflow. This aligns with what you're seeing: exportItems can export events, however attempting to upload an event through the importUrl generated by createImportSession results in a failure.

    If your goal is to migrate or recreate calendar items, the supported approach is typically to create events via the Calendar APIs (POST /users/{id}/events or related calendar endpoints) rather than using the import session mechanism.

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