During the extraction of a PST, several issues can occur. The most common issue is the reprocessing of the successfully extracted files.
You can easily identify this issue. When the Extraction process fails, the file gets status: Not a PST File by System.
By checking the details you can see the error: Failure The files is not in PST format. Size is 0 bytes!
By design, the successfully extracted file is set to size 0 bytes. Its content is extracted to another container/directory.
If you want to run Extraction again, you have to provide a backup of this file and after then you can reprocess extraction.
Here are the steps you should do:
1) Locate, where is PST file you want to reprocess -> On file – Right click and choose Show user. This will take you to the User screen
2) On the User screen you have to check the assigned profile. In a multi-location environment, you can easily determine, where is Backup and Upload location for this user and his/her files
2) Identify the PST you want to reprocess. (eg. you want to reprocess file -123_example_123456.pst)
3) Copy this PST from the Backup directory to the Uploads directory. In Backup it is called backup_-123_example_123456.pst
4) Remove prefix “backup_” from files (e.g your file will be then -123_example_123456.pst). It is possible that the 0-byte file is still in the Upload directory and will make a conflict when you try to do so. Prior to renaming, delete 0 byte -123_example_12345.pst
5) Check directory -123 inside the Uploads directory. If it is there move it to some other location or delete it
5) Check-in CleanUp directory if there is old PSTfile DB content (e.g -123_example_123456_db.zip). If such file exists move it to some other location or delete it
6) In Manage>Files select file you are going to reprocess (e.g. -123_example_123456.pst) and press Reprocess Module
7) Window will be opened, where you need to select what you want to reprocess, select all from the top including Extraction and hit Reprocess and Migrate
8) Extraction will start shortly after and PST will be reprocessed
Second most common issue with Extraction is timeout.
Be default Extraction timeout for file is 10 minutes. In case of big files this time may not be sufficient.
You can identify this issue in detailed view of a file:
“EXCEPTION: QUADROtech.FlightDeck.PostProcess.UnresponsibleProcessTerminatedException: Worker process [XXXX] was terminated, because it didn’t update its status for  minute(s).”
To extract the multi GB files you may extend extraction time. This KB article will help you: