Archive Shuttle uses a new library to manipulate PST files in the Native Format Import Module. The following error may be seen in the log files:
2015-04-22 04:57:05Z|7688| 13| INFO| ImportToPst|Queued new command [ImportToPst], commands currently queued , running  2015-04-22 04:57:31Z|7688| 7|ERROR| LogOutOfMemoryException|This exception occurs only with 32bit module version once total attachment size of single message exceeds 10MB limit. Anything above this limit is not guaranteed therefore it's advised to use 64Bit version. 2015-04-22 04:57:31Z|7688| 7|ERROR| Ingest|Ingestion to file failed Void QueryEnd(Boolean) One or more errors occurred.
The 64-bit Native Format Import Module should be used, by default if the Operating System is 64-bit, then the 64-bit module will be deployed.