Incorrect output when you run Get-CASMailbox to view HasActiveSyncDevicePartnership

Original KB number:   3001236


In a Microsoft Exchange Online environment, you run the Get-CASMailbox cmdlet to view the HasActiveSyncDevicePartnership attribute. The output shows that the mailbox has no device partnership. However, the user has one or more devices that are synchronizing with their mailbox.


To resolve this issue, run the following command:

Get-CASMailbox <Alias> -RecalculateHasActiveSyncDevicePartnership


The RecalculateHasActiveSyncDevicePartnership parameter was introduced to the Get-CASMailbox cmdlet in build 15.00.0980.000 of Microsoft 365. To determine the build of Microsoft 365 that the mailbox is on, run the following command:

Get-Mailbox <Mailbox> | fl AdminDisplayVersion

More information

The RecalculateHasActiveSyncDevicePartnership parameter recalculates the value of the HasActiveSyncDevicePartnership attribute on the mailbox. The value is automatically updated if it's determined to be incorrect. You don't have to specify a value for the HasActiveSyncDevicePartnership attribute.

For more information, see Get-CASMailbox.

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