EO - mailbox folder permission for Usertype unknown - how to remove ?!

Daniel Hnyk 56 Reputation points
2021-07-01T05:22:45.153+00:00

Hello guys, i would like to get some advice, how to remove mailbox folder permission for usertype Unknown in ExchangeOnline

I am connected to exchange online via PS with prefix EO as Exchange Online, so cmdlets will start with EO, because we have hybrid environment and i need to manage both in one PS.

I have shared mailbox, where is some corrupted ACL for user group, which i want to remove.

[PS] C:\ExchangeScripts\ExchangeOnline\Resource Migration>(Get-EOMailboxFolderPermission "Mailbox") | select -ExpandProperty user

UserType RecipientPrincipal DisplayName


Default Default
Anonymous Anonymous
Unknown %GroupName%

so i am able to select this unknown UserType:
Get-EOMailboxFolderPermission -identity "Mailbox" | where {$_.user.usertype -like "unknown"}

But i cannot remove this rights, through pipeline:

Get-EOMailboxFolderPermission -identity "Mailbox" | where {$_.user.usertype -like "unknown"} | Remove-EOMailboxFolderPermission

Cannot process argument transformation on parameter 'User'. Cannot convert value "GroupName" to type "Microsoft.Exchange.Management.StoreTasks.MailboxFolderUserIdParameter". Error: "Cannot convert hashtable to an object of the following
type: Microsoft.Exchange.Management.StoreTasks.MailboxFolderUserIdParameter. Hashtable-to-Object conversion is not supported in constrained language mode, restricted language mode or a Data section."

  • CategoryInfo : InvalidData: (Microsoft.Excha...olderPermission:PSObject) [Remove-MailboxFolderPermission], ParameterBindin...mationException
  • FullyQualifiedErrorId : ParameterArgumentTransformationError,Remove-MailboxFolderPermission
  • PSComputerName : outlook.office365.com

I dunno, why it returns that error described upper....

Do you have any ideas how to deal with it?

Thanks you

D.

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Accepted answer
  1. KyleXu-MSFT 26,206 Reputation points
    2021-07-02T01:41:34.867+00:00

    @Daniel Hnyk

    Try to recover this mailbox, then check whether this "Unknown" user become visible on this permission list.

    If you cannot recover this mailbox, you can try to create a service request to Office 365 team, check whether they could delete this permission from the backend.

    If they cannot remove the permission for you, I think you may need to recreate this mailbox. In this way, all permission on this mailbox will gone. But you need to add needed permission back to this mailbox again.


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    1 person found this answer helpful.

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  1. Jürgen Barth 0 Reputation points
    2023-09-18T10:02:35.5933333+00:00

    even if the thread is old ...

    I have the same problem, did you ever solved this problem?
    I was told to reset the delegates, but this doesn´t help.