# 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``.ini` file.

      [container_flags]
      detectPSTbyExtension=1

NOTE: The `detectPSTbyExtension` option only applies when you are using the MAPI reader (pstsr).

NOTE: 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 will not be available to verify the file type and pass the file to the appropriate reader.

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