I am wondering if there’s a way to open and check the contents of an old PST file if I don’t have Outlook installed in my machine?
For OS X, there is PST Bridge. It isn't free though.
You can import PSTs to a number of other email applications (HA14 mentioned Thunderbird, but there are others), so it's really a question whether you want to actively and regularly have access to the emails, in which case you should import them to your mail application, or just for occasional access, in which case you should use PST Viewer.
Yes, it is basically for occasional access. I have a couple of old PST files that I'd like to go through, but I don't have MS Outlook installed in my machine.
I'll give PST viewer a try
You can import pst to thunderbolt
PST Viewer will do the trick. The interface even looks similar to Outlook.
Sure, you can view and read pst file data without installing ms outlook using any pst viewer application. Almost all pst viewer application are free so far but allows reading of only healthy pst file data. Here is an advance application called Recover Outlook basically designed to recover deleted & corrupted pst file data. Its demo edition works as PST viewer that scans corrupted & damaged pst file and shows all elements (emails, contacts, calendars, tasks, notes, journals etc) of pst file in tree view with their meta data details. All data can be easily explored and viewed without investing any amount.
To scan & view pst file data, the product does not require ms outlook installed on your machine but to save scanned and recovered data into any format (PST, EML & MSG), you need to install ms outlook and purchase its license edition.
Start with free trial:
I think X1 Search as found at http://www.x1.com/ can index and allow you to search the contents. I am not aware of any other programs than Outlook for actually opening the PST files. Good luck in your search.