# 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 body text and header information (`To`, `From`, `Sent`, and so on) from each Outlook item are 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, using the `SaveAsMSG` property in the `ExtractSubFileExtractConfig` class.

If an Outlook item contains a non-mail attachment, the attachment is extracted in its native format to a sub directory. If an Outlook item contains an Outlook attachment, the attached item's body text and attachment(s) are extracted to a sub directory.

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.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`.

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