Does moving a message item between folders in a shared mailbox modify its immutable id? (Note: It's a shared mailbox))

Question

I am using the Graph API .NET SDK to fetch messages in a shared mailbox and adding the prefer immutable ids header. However, when paginating the results using the odataNextLink property & fetching the entire result, the immutable ids of message item gets modified when they are moved to a different folder. Is this expected behavior?

Answer 1

I have found that when using the Microsoft Graph API to move the message betwen folders in a shared mailbox, the immutable ID does not change.

However, when using the Windows and Web Outlook clients to move a message in a shared mailbox, it appears to create a copy in the destination folder and move the original to a hidden "Purges" folder, which results in the message getting a new immutable ID in the new folder.

Answer 2

Hi,

An item's immutable ID won't change so long as the item stays in the same mailbox. That means that immutable ID will NOT change if the item is moved to a different folder in the mailbox.

Even if it is a shared mailbox, it should be the same as above.

However, the immutable ID changes if:

• The user moves the item to an archive mailbox.
• The user exports the item (to a PST, as an MSG file, etc.) and re-imports it into their mailbox.

More information you can refer to: : Obtain immutable identifiers for Outlook resources - Microsoft Graph | Microsoft Learn

Please feel free to contact me for any updates.