# Extract Subfiles from Outlook Personal Folders Files

KeyView can extract Outlook items such as messages, appointments, contacts, tasks, notes, and journal entries from a PST file. When a PST file is extracted to disk, the text and header information (`To`, `From`, `Sent`, and so on) from each Outlook item is extracted to a text file. (If you do not want the header information to appear in the text file, see Exclude Metadata from the Extracted Text File.)

You can also extract messages from PST files as MSG files, including all their attachments, by setting the `KVExtractionFlag_SaveAsMSG` flag in the KVExtractSubFileArg structure when you call `fpExtractSubFile()`.

If an Outlook item contains a non-mail attachment, the attachment is extracted in its native format to a subdirectory. If an Outlook item contains an Outlook attachment, the attached item’s text and any attachments are extracted to a subdirectory.

NOTE: The Microsoft Outlook Personal Folders (PST) readers are an advanced feature and are sold and licensed separately. To enable these readers in a KeyView SDK, you must obtain an appropriate license key from Micro Focus. For information about adding a new license key to an existing installation, see Pass License Information to KeyView.

## Choose the Reader to use for PST Files

KeyView provides several ways of processing PST files:

- Indirectly, using the Microsoft Messaging Application Programming Interface (MAPI). MAPI is a Microsoft interface that enables different applications to exchange messages and attachments with each other. MAPI allows KeyView to open a PST file, traverse the folders, and extract items. The `pstsr` reader uses MAPI, but works only on Windows and requires that Microsoft Outlook is installed.
- Directly, without relying on the Microsoft interface to the PST format. Accessing the file directly does not require Microsoft Outlook. The `pstxsr` reader is available only on certain platforms (see pstxsr in the platform differences section). The `pstnsr` reader is an alternative native reader, for the platforms not supported by `pstxsr`.

On Windows, the MAPI-based reader is used by default but you can choose `pstxsr` if you prefer. On non-Windows platforms, only one of the native readers is available.

The differences between the readers are summarized in the following table.

Feature | Native Reader (pstxsr) | Native Reader (pstnsr) | MAPI-based Reader (pstsr)
--- | --- | --- | ---
Platforms supported | Windows x86 and x64 Linux x64 and AArch64 | All platforms not supported by `pstxsr` | Windows x86 and x64
Outlook required | No | No | Yes
MAPI properties supported | Yes. All properties defined in `mapitags.h`. Object properties are not supported.
Password protection supported | Yes | Yes | Yes (using `KVCredential` structure)
Compressible encryption supported | Yes | Yes | Yes
High encryption supported | No | No | Yes

To change the reader used to process PST files, change the PST entry (file category value `297`) in the `formats_e.ini` file. For example, to use `pstxsr`:

    297=pstx

NOTE: You must make sure that the PST that you are extracting is not open in the Outlook client, and that the Outlook process is not running.

NOTE: When extracting subfiles from PST files, information on the distribution list used in an email is extracted to a file called `emailname.dist`. This applies to the MAPI reader (`pstsr`) only.

### System Requirements

MAPI is supported on Windows platforms only and relies on functionality in Outlook. If you want to use the MAPI-based reader, `pstsr`, Microsoft Outlook must be installed on the same machine as your application. Outlook must also be the default email application. KeyView supports the following PST formats and Outlook clients:

- Outlook 97 or later PST files

  NOTE: The Outlook client must be the same version as, or newer than, the version of Outlook that generated the PST file.

- Outlook 2002 or later clients

  NOTE: You must install an edition of Microsoft Outlook (32-bit or 64-bit) that matches the KeyView software. For example, if you use 32-bit KeyView, install 32-bit Outlook. If you use 64-bit KeyView, install 64-bit Outlook.

  If the editions do not match, KeyView returns `Error 32: KVError_PSTAccessFailed` and an error message from Microsoft Office Outlook is displayed: `Either there is a no default mail client or the current mail client cannot fulfill the messaging request. Please run Microsoft Outlook and set it as the default mail client`.

## MAPI Attachment Methods

The way in which you can access the contents of a PST message attachment is determined by the MAPI attachment method applied to the attachment. For example, if the attachment is an embedded OLE object, it uses the `ATTACH_OLE` attachment method. KeyView can access message attachments that use the following attachment methods:

    ATTACH_BY_VALUE

    ATTACH_EMBEDDED_MSG

    ATTACH_OLE

    ATTACH_BY_REFERENCE

    ATTACH_BY_REF_ONLY

    ATTACH_BY_REF_RESOLVE

Attachments using the `ATTACH_BY_VALUE`, `ATTACH_EMBEDDED_MSG`, or `ATTACH_OLE` attachment methods are extracted automatically when the PST file is extracted. An "attach by reference" method means that the attachment is not in Outlook, but Outlook contains an absolute path to the attachment. Before you can extract these types of attachments, you must retrieve the path to access the attachment.

To extract "attach by reference" attachments

1. Determine whether the attachment uses an `ATTACH_BY_REFERENCE`, `ATTACH_BY_REF_ONLY`, or `ATTACH_BY_REF_RESOLVE` method by retrieving the MAPI property `PR_ATTACH_METHOD`.
2. If the attachment uses one of the "attach by reference" methods, get the fully qualified path to the attachment by retrieving the MAPI properties `PR_ATTACH_LONG_PATHNAME` or `PR_ATTACH_PATHNAME`.
3. You can then either copy the files from their original location to the path where the PST file is extracted, or use the Export API functions to convert the attachment.

## Open Secured PST Files

KeyView enables you to specify a user name and password to use to open a secured PST file for extraction.

To open password-protected PST files that use high encryption, you must use the MAPI-based PST reader (`pstsr`). The native PST readers (`pstxsr` and `pstnsr`) return the error message `KVERR_PasswordProtected` if a PST file is encrypted with high encryption.

## Detect PST Files While the Outlook Client is Running

If you are running an Outlook client while running the File Extraction API, the KeyView format detection module (`kwad`) might not be able to open the PST file to determine the file’s format because Outlook has the file locked. In this case, you can do one of the following:

- Close Outlook when using the Extraction API.

- Detect PST files by extension only and bypass the format detection module. To enable this option, add the following lines to the `formats_e.ini` file:

      [container_flags]
      detectPSTbyExtension=1

  The `detectPSTbyExtension` option applies only when you are using the MAPI reader (`pstsr`).
  If you use this option, you must make sure in your code that valid PST files are passed to KeyView, because the format detection module is not available to verify the file type and pass the file to the appropriate reader.

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