When extracting data from an Enterprise Vault 2007 journal mailbox the following may be logged:
EXCEPTION: System.Runtime.InteropServices.COMException (0x80040306): An internal failure occurred. Internal Error: '<0x4005>'.
960707 10:51:46.944  (StorageOnlineOpns) <7588> EV:M CSimpleStore::FetchItem6 exception raised
Exports will not be performed, because of this error.
The above errors were observed with Enterprise Vault 2007 SP 6
Symantec has issued End of Life Statements for many versions of Enterprise Vault, this version included. Therefore they do not offer break-fix support for any issues regardless of customer or severity.
Quadrotech wants to do what they can in order to expedite issues of this matter. In our internal testing it was discovered that upgrading the environment from EV 2007 SP 6 to EV 8.0.5 resolved the export issues. It is therefore recommended that this is tried after taking all appropriate backups of the environment.