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Starting May 1st, 2018, we will no longer offer the ArchiveOne family of products. This includes all editions of ArchiveOne, ArchiveOne for Files, Max Compression, and Access Security Manager. If you currently hold a maintenance and support contract, you will continue to receive our award-winning support until your contract expires, or until May 1st, 2019, whichever occurs first. The license for ArchiveOne is perpetual; therefore the software may continue to be used independently without any updates or support indefinitely.

Understanding the PST Processor

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Message Processing

In addition to processing messages in mailboxes and public folders, ArchiveOne can process messages in Personal Storage (PST) files. This can be done against PSTs that are attached to a user's Outlook profile as well as PSTs that are uncoupled, that is, PSTs not connected to an Outlook profile, by specifying base directories on disk in which to search for PST files. For information on running PST processing for the first time, refer to the Quick start guide for PST Processing in ArchiveOne.

If you intend to use the PST Processor to process uncoupled PSTs associated with mailboxes hosted on Office 365/Exchange Online, contact Support.

Once a PST file is found, there are two PST file operations available; select the option that meets your requirements. Note that, typically, the more data the operation gathers, the longer processing takes:

  • Simple discovery – Records the PST filename, path, and size, for review at a later time. 
  • Policy – In addition to the data recorded by simple discovery, applies any policy criteria and actions, in order, for instance, to find messages containing a given word, or copy messages with attachment with a given file extension to a public folder. To define a PST policy, use the Policies Node

PST archiving makes use of a temporary area within the Server Data Location to store messages for archiving (configured by running the Configuration Wizard). PST data rests in this area between being found by the PST Processor and being archived, typically a few hours or less. The PST Tuning setting allows you set a limit on the size of this temporary cache. Ensure there is sufficient disk space in the Server Data location to accommodate the size of the cache you have configured. Increase the cache size to upload more PST data for archiving at any one time.

  If you change the Server Data Location and you have already begun archiving PSTs but archiving is not completed, you must move all the data from the old location to the new location.

The PST Processor sends data through the Search and Retrieval Website to the ArchiveOne Service to be added to the archive. Ensure that any PCs that are to run the PST Processor have all configuration required to access the Search and Retrieval Website without prompting. For example, if your Search and Retrieval Website is accessed through HTTPS, the PC running the PST Processor must have the necessary certificates installed and trusted so that users are not prompted for authentication or certificate acceptance.

When the ArchiveOne service is installed, a subdirectory of the installation directory is created (by default, C:\Program Files (x86)\Barracuda\ArchiveOne\Pst Processor) and shared as PstProcessor. This shared folder contains all the files required for PST processing. This includes 32- and 64-bit versions of the PST processor, and supporting components for running IFiltering when necessary. You can copy the PST processor from this folder to another location (it does not need to be installed on the server from which it is run), but if you do so, then you must also copy all files in the shared folder.

If you want to run PST Processing, you must first run AOnePolPSTProc.exe on the client machine:

  • For coupled PST discovery and processing, this is typically done when users log into their systems through a login script. This provides access to the currently logged on user's Outlook session so that the PST Processor can access any coupled PST files.
  • For uncoupled PST discovery and processing, this can be run under the context of any user, for example, using a login script, or running manually from the command prompt. However, the user who runs the PST Processor must have the necessary rights to log into the mailboxes that are to be associated with the PSTs found. For example, if a PST is going to be associated with mailbox X then the user running the PST Processor must have rights to log into mailbox X because, for instance, the policy action may be to move data from the PST into the mailbox. Running the PST Processor under a login script can only process uncoupled PSTs associated with that user's mailbox, and PSTs associated with other user mailboxes to which the current user has access rights. As non-administrative users do not typically have access to other user's mailboxes, processing in uncoupled mode is typically done by an administrator from the command line, not by login script for individual users. 

    In versions of ArchiveOne prior to 6.3, the PST Processor was configured using command line options. With version 6.3 and later, the only command line option required for the PST Processor is the URL of a service, AOnePstManagement.asmx, which provides its configuration. 


  • To launch the PST Processor from the command line or via a script, run the following command:
    Where myarchiveserver represents the Archive server name (or the new share location if you have moved the PstProcessor share to another machine), and mywebserver represents the name of the server hosting the Search and Retrieval Website.
    Use HTTPS rather than HTTP if you have configured a valid SSL certificate and enabled this on the web server.
    In the PstProcessor shared directory there are executables for both 32- and 64-bit, however you should always launch the 32-bit executable. When appropriate, it automatically transfers control to the 64-bit executable.

To configure the PST Processor behavior, for example, where to search for PST files, use the PST Processor Configuration dialog in ArchiveOne Admin described in Coupled and Uncoupled PSTs Nodes.

PST Processor Operation

If run only in coupled mode (looking for PSTs in Microsoft Outlook), the program waits until Outlook starts and a user has logged in, then checks to see if any policies are configured and processes accordingly. If run in uncoupled mode (looking for PSTs on local hard drives), the program checks to see if any policies are configured, and if so, searches the specified path(s) for PSTs and processes accordingly. If you have specified both coupled and uncoupled mode, the coupled mode is performed first. If Outlook is not open, then the PST Processor proceeds to uncoupled mode. However, uncoupled PSTs must be associated with a mailbox before they can be processed. In order to run a policy against a PST file, the owner of the data must be defined. You can either manually assign the owner of a PST file, or have the PST Processor attempt to determine this automatically using the Try to determine the owner of a PST option on the Miscellaneous tab in the Client Configuration.

If you want to run a policy against a PST file, you must create a PST policy in the ArchiveOne Admin console. For example, you can configure a date range through which you want the search to be performed, or specify particular users or PST files you wish to apply the policy to.

If processing uncoupled PSTs, they must be associated with a mailbox. This is necessary for policy actions, such as archive, so that when the PST items are archived, they are stored as though they were from the specified mailbox. Additionally, any user allowed to search into the mailbox archive is also allowed to search these PST items. If there is no mailbox associated with a PST, for example, you have not configured the option to automatically determine the owner, or this option is enabled but the owner could not be determined automatically, the PST cannot be processed. To associate a mailbox for a PST, find the PST listed in the Uncoupled PSTs node, right-click on it, and click Set Mailbox.

If a user has password protected PST files, when they run AOnePolPSTProc.exe they may be prompted for the PST file password. If they do not enter the password, then only simple discovery happens for the PST file.

On a client machine, to see how the individual PST processing is progressing, right-click the PST Processor icon in the tool tray, and click show to view current activity details. Alternatively, you can hover the mouse over the tool tray icon to see a progress summary.

At any time you can see what PST files have been discovered so far. Go to the Coupled and Uncoupled PSTs Node node in ArchiveOne Admin. PST files may be found and processed by either coupled or uncoupled PST processing. The same PST may appear on both the Coupled PSTs node and the Uncoupled PSTs node. For example, if a coupled PST file located on disk in a location you have configured to search during uncoupled processing, it is found and reported under Coupled PSTs as it is open in Outlook. When uncoupled processing scans the specified locations, it is found and reported under the Uncoupled PSTs node. However, PST files which are listed under both Coupled and Uncoupled PSTs are preferentially processed using coupled mode (as Outlook will have a lock on the PST file).

PST Processing for Archiving

To process a PST file you must define a PST policy. You can create as many PST policies as required, defining specifically which PST files these policies apply to and what actions should be carried out.
Typically you create a number of policies to archive and stub messages in PST files to an appropriate repository based on the message delivery date, for example, a message received in 2015 is archived to your Year_2015 repository and the original item in the PST file is then stubbed. Once all the messages in the PST file are stubbed, you can choose to migrate the message stubs from the PST file to the owner’s mailbox. The PST file can now be disconnected and the end user can easily retrieve their archived data from the message stubs in their mailbox.

Alternatively, if you have large storage allowances in Exchange, you can choose to migrate all or some of the data from the PST files directly to the Exchange mailbox without archiving. The benefit of archiving and stubbing the messages first is that the stub is significantly smaller than the original email. This reduces the volume of data ingested into Exchange. However, archiving and stubbing a message directly from the Exchange mailbox is faster than archiving the data from the PST file. The ArchiveOne service, which is responsible for the archiving process, can communicate and interact directly with the message data in Exchange. When the message data for archiving is held in a PST file, the ArchiveOne service makes use of the PST Processor to access this data; the PST processor is responsible for uploading data to the ArchiveOne service for archiving and then subsequently stubbing the data in the PST file when archiving takes place. This stepped process by definition is slower than the direct Exchange interaction available during mailbox processing.

If you have limited Exchange storage, then archiving and stubbing the PST file first reduces the size of the data ingested into Exchange. Additionally, you can choose to archive without stubbing and delete the original message from the PST file, and not import any data from the PST file into Exchange. Though the user will not have a message stub in their Exchange mailbox, they can still access their archived data from the Archive Search (AOneSearch) website by browsing or searching. Depending on the storage available in Exchange, you can archive and stub data which is less than a year old and archive and delete any data older than a year from the PST file. The user has the benefit of some message stubs within the last year ingested into their mailbox for ease of access. Any older data can then be retrieved from the Archive Search website, if required.

See Understanding PST Migration for more information.


You cannot create a PST policy with an unarchive action. If you have archived a PST file and need to unarchive the data, you can either:

  • Run a policy to migrate the data to a mailbox and then run a mailbox policy with an unarchive action against this data once in the mailbox; or
  • Run an archive search from the ArchiveOne admin console and then retrieve the search results to a PST file.


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