How to delete a TargetRoot folder with PowerShell

Hi everybody

A few weeks ago we had a Problem with Outlook Calendar Items. They were deleted with an external program to fix some other issues. To resolve this we have restored the the calendar with the following PowerShell command:

New-MailboxRestoreRequest -SourceStoreMailbox "Username" -SourceDatabase "recovery" -TargetMailbox "Username" –TargetRootfolder Restore –IncludeFolders 'Calendar','Kalender'

This works fine.

Now I'd like to delete this Rootfolder "Restore". But Outlook says I have not enough permission to do this. So I checked this out with the following Powershell cmd:

Get-Mailbox -Identity <Username> | ForEach-Object {Get-MailboxFolderPermission $_":\Restore"} | fl

The result is, I am the Owner of this folder.

How can I delete this Rootfolder now?

I hope u guys have a good hint or a resolution for this problem.