Symptoms
When you copy messages to a Discovery mailbox by selecting the Copy Search Results option in eDiscovery in a Microsoft Exchange Server 2013 environment, you receive an error message that resembles the following:
Failed exporting item id: from source id: SourceID with error: [NumberOfItemsMismatched] Export failed with error type: 'NumberOfItemsMismatched'. Message: Expected number of items (Number) supposed to write to the list is not matched with actual (Number)
Resolution
To resolve this issue, install the following cumulative update:
2892464 Description of Cumulative Update 3 for Exchange Server 2013
Status
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
More Information
For more information about the Copy Search Results option in eDiscovery, go to the following Microsoft website: