Stellar PST Viewer is a free tool for viewing Outlook PST files - all versions from 2000 to 2013 - even if they're corrupt.
The program scans for emails, calendars, contacts, notes, tasks and more, displays them in a reasonably Outlook-like interface, and allows you to save individual emails as EML, MSG, HTML, RTF or PDF files.
This all starts by pointing the program at your PST file. You can browse to it directly, or use a search tool to locate it.
Stellar PST Viewer then scans the file to recover and organise its data. This doesn't seem to be a very efficient process - it builds your PST tree as you watch, adding items one at a time, leaving them scrolling down your screen - and can take quite some time. We tried the program with a 4GB PST and were waiting for around 55 minutes.
Once this is done, an Outlook 2013-like panel helps you browse through your mail, calendar and contacts. You're able to find and expand any email folder, sort or search it by various parameters (From, To, Subject, Date), read individual emails and save them to separate files.
What you can't do, bizarrely, is search for messages by their body text. There's no option to display or save attachments, and you can't select and save multiple files at once: it's strictly one at a time.
Stellar PST Viewer has even fewer recovery options for other PST data. You can view calendar details, but there's no option to save them, even individually. And Contacts are displayed in a hard-to-read tiled format which, on our system at least, meant that most addresses weren't fully visible. To view them properly we had to hover a mouse cursor over that contact and wait for it to be displayed as a tooltip.
One final issue is that we suspect Stellar PST Viewer requires Outlook to be installed before it can save individual emails, perhaps a problem if you're only interested in recovery.
Stellar PST Viewer did a good job of scanning our PST file, finding and displaying emails. But it's also slow, with a weak search tool, poor interface, and very limited recovery tools. It might be useful if you just want to view one or two emails or other items, otherwise give it a miss.