Failed to read mail : MAPI_E_INVALID_ENTRYID

Failed to read mail : MAPI_E_INVALID_ENTRYID

Symptoms

The error is reported while running Message Level Restore emails backup set protecting Exchange Public Folders

Cause

1. The backup items list includes public folders containing items with identical Exchange id and the DS-MLR service account does not have rights to re-assign a different id ( DS-MLR automatically assign unique Exchange ids for items having a duplicate id if the registry key HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\DS-Message Level Restore\Parameters\ChangeDuplicateID is set to 1 ).2. At the beginning of a backup session (for an emails backup set) the mailboxes to be backed up are scanned in order to identify the items to be backed up, then the items that have to be backed up are open and read by a backup thread, if during the very short time between folder scanning and opening an item the object is moved or removed from its original location then the error MAPI_E_INVALID_ENTRYID is reported.
   3. Client permissions for the DS-MLR service account (grant "Publishing editor" permissions) on the public folders top level but not propagated to subfolders under the public folder

Workaround

1. Adjust the client permissions for the DS-MLR service account (grant Publishing editor permissions) on the public folders intended to be backed up and reporting the error.
   Set the permissions via PFDAVAdmin tool ( for Exchange 2007 ) and via Exchange Management Console or Exchange Management Shell for Exchange 2010.
   Using the Exchange Management Console :
   a) Toolbox Public Folder Management Console ( open tool )
   b) Highlight the Default Public Folders on the left side, highlight the desired folder in the middle pane, then click on Properties on the right side Permissions Add, select and add the DS-MLR service account, choose Publishing Editor from the drop-down list available for the Permissions level field, save the changes and then try the backup again (no need to restart the DS-MLR service ).
   2. no action needed, the error will clear itself during the next backup session.
   3. Apply/ propagate the permissions using the option: Exchange Admin console (Exchange 2010) –> Toolbox –> Public Folders –> Select a public folder –> Manage Public Folder Settings –> Update Client Permissions and check the 'Apply Client Permission Changes to this folder and all its subfolder