Error Message

The operation couldn't be performed because object '/Users/Administrator\0cc6d075-e610-4b8a-90c6-1460e6d4d710'  couldn't be found on 'Microsoft.Exchange.Data.Storage,MailboxSession'.

This error can occur if there is an issue with the Arbitration mailbox associated with the Exchange Server.

History of Arbitration mailboxes:

Since Exchange 2003, Microsoft has introduced specific mailboxes to manage system operations.

With Exchange 2013, these mailboxes are becoming more important. For example, these mailboxes are used to operate mailbox moves or OAB (online address book) generation.

Exchange related functions that are likely to fail :

• Local exchange server mailbox move fails to complete.
• Standard OWA Apps (task, appointments) missing
• Unable to install any OWA Apps at Organization level however users can install Apps from their mailboxes.
• No new OAB generation (Default Offline Address Book )
• Export to pst does not work properly
• Grammar and spell check not working

To determine if the Arbitration mailbox is problematic, execute the following Exchange Management Shell Command:

Get-mailbox -Arbitration | fl name,persis*

The results for a working environment should return the PersistedCapabilities for all Arbitration mailboxes, and by default for SystemMailbox {bb558c35-97f1-4cb9-8ff7-d53741dc928c}) the below should be listed:

========================================
Name  : SystemMailbox{bb558c35-97f1-4cb9-8ff7-d53741dc928c}

PersistedCapabilities : {OrganizationCapabilityClientExtensions, OrganizationCapabilityPstProvider,

                                           OrganizationCapabilityMessageTracking, OrganizationCapabilityUMGrammarReady,

                                            OrganizationCapabilityMailRouting, OrganizationCapabilityOABGen,

                                            OrganizationCapabilityUMGrammar}
========================================

Note: Deployment of any type of OWA Apps at the Organization level will fail if the PersistedCapabilities: OrganizationCapabilityClientExtensions is not present for SystemMailbox {bb558c35-97f1-4cb9-8ff7-d53741dc928c}).

• Launch Adsiedit.msc or DSA.msc attribute editor. 
• Locate SystemMailbox{bb558c35-97f1-4cb9-8ff7-d53741dc928c} and select properties
• In the Attribute Editor tab - locate the msExchCapabilityIdentifiers attribute

Ensure the values (52:51:47:46::44:43:42:40) are present