PST file won't open—how can I recover my emails?

I would not convert the PST files to PDF before importing them. PDF is useful for reading or archiving messages, but it cannot preserve a working Outlook mailbox structure the way a PST can.

First, try opening and repairing a copy of each PST with classic Outlook:

1. Make a backup copy of the PST and keep the original untouched.
2. In classic Outlook, open File > Open & Export > Open Outlook Data File.
3. If it will not open, close Outlook and run Microsoft’s Inbox Repair Tool, SCANPST.EXE.
4. Select the copied PST, run the scan, enable the backup option and repair the file.
5. Reopen the repaired copy in Outlook. A badly damaged PST may need more than one scan.

Once it opens, import it into your Microsoft 365 mailbox:

1. Open File > Open & Export > Import/Export.
2. Select Import from another program or file.
3. Choose Outlook Data File (.pst).
4. Select the PST and its top-level folder.
5. Enable Include subfolders and import it into your Microsoft 365 mailbox.

This should preserve the Outlook folders, messages and attachments. Check the mailbox storage limit first. For several very large PST files, ask the Microsoft 365 administrator to use the Microsoft 365 PST Import service instead of importing everything through Outlook.

For PDF copies, classic Outlook can print individual messages through Microsoft Print to PDF, but attachments and folder structure are not preserved automatically. For bulk PDF archiving, Adobe Acrobat Pro’s Outlook integration is a paid option that can convert selected messages or folders and create a PDF Portfolio containing attachments. Repair and open the PST in Outlook before using it.

Avoid uploading work PST files to an unknown online converter because they can contain years of private messages and attachments.

If you're having trouble opening your PST files and need to convert them without losing attachments or folder structure, consider trying tools that can directly access and read PST files without Outlook. One such tool is https://openpst.com/, which lets you view and extract content from PST files. It might not handle direct PDF conversion, but it can help you access the emails and attachments, which you can then save in a format suitable for conversion. This could be a useful step if you're struggling with inaccessible PSTs on your new setup.

Dear jonhscott, if your PST file is not opening, it means your PST file might be affected by a Trojan virus or corrupted due to an accidental shutdown of your computer system. But you can still repair and recover your data. Microsoft Outlook provides its official tool name as SCANPST.EXE. Use this tool to repair your PST file. Once the repair is done, your Outlook PST file will run normally.

Back up every PST first. If one will not open, close Outlook and run SCANPST.EXE against a copy; repeat if it reports remaining errors. Then use classic Outlook to import each repaired PST: File > Open & Export > Import/Export > Import from another program or file > Outlook Data File. Select the Microsoft 365 mailbox and enable Include subfolders. This supported route retains message attachments and folder hierarchy.

For many users or large batches, ask a Microsoft 365 administrator to use Purview’s PST Import service with network upload and a mailbox mapping file. Keep the original PSTs until item counts and spot checks match. PDF is separate: Outlook can print individual messages to Microsoft Print to PDF, but Microsoft provides no bulk PST-to-PDF workflow that preserves folders and attachments. Avoid converters until your organization has reviewed their security and compliance.