Troubleshooting & FAQ

Solutions to common questions and problems.

macOS or Windows won’t open the app

The Windows installer is not code-signed yet, so SmartScreen asks for confirmation on the first launch (older Mac downloads were not signed either). See First launch: confirming the app for the steps.

A file won’t open

Check that it is a supported file: PST, MSG, EML or MBOX.
OST files (Outlook offline data files) are not supported yet.
If the file is in a cloud folder, make sure it has been fully downloaded to your device.

Search doesn’t find a message

Right after opening, the full-text index is still being built – matches in message bodies may be missing until it is complete.
Check the search scope: is Current Folder selected instead of All Folders?
Check the filter chips below the search field and reset them if necessary.
Write operators without a space after the colon: from:anna. See query syntax.

Images are missing in an email

Remote images are blocked to protect your privacy. Choose Load Images to show them for that message.

An attachment won’t open

For security reasons, PST Viewer never opens file types that can run code directly. Only save such a file if you trust the sender. For other files without a preview, choose Open in Default App.

A message is encrypted

PST Viewer cannot decrypt encrypted S/MIME messages because the private key is not part of the file. Digitally signed messages, on the other hand, are displayed.

Does PST Viewer change my file?

No. All files are opened strictly read-only. See Read-only – a promise.

Report a bug or suggest a feature

PST Viewer is developed in public on GitHub. Please report bugs and share ideas as an issue – and never attach real mailboxes or private messages. Pull requests are welcome, too.