By default, X1 will index all PST files mounted in your Outlook profile.
If you have an archived PST that is not mounted in your Outlook profile, you can add the PST directly to X1 by following the steps below:
1. Select Tools > Options
2. From the Basic Options screen, select Outlook, located under the Email heading
3. Click Select Folders to Scan
4. Select the Add PST File(s) button
5. Select the PST file(s) and click OK, you will need to update your index for these items to become searchable.
Please Note: Adding the same PST file through both Outlook AND X1 directly will create conflicts.