What is a PST file?

A .pst (Personal Storage Table, or PST) file is a special file type created by Microsoft for their Outlook email app. When you use Outlook, it stores all your emails, attachments, calendar events, etc. in a PST file. So, it's like a single file acting as a folder (In fact, Microsoft calls them personal folders

PST files were very useful in the past since a lot of data could be stored in a relatively low file space, and it could be stored locally on your computer instead of taking up storage space on an email provider's online servers. Storing it locally meant you could access the information offline.

Note: Microsoft Outlook is different from Microsoft Outlook Express - don't confuse the two! Outlook Express is a simpler version of Outlook and uses .dbx files instead of PST files. Outlook Express's .dbx files aren’t encrypted, and messages are stored as plain text. Outlook's PST files are more secure, as messages are compressed and stored in a database.

But PST files have their problems:

  • They are easily corrupted if used by more than one user at a time
  • They were made to be used only on one device
  • They complicate eDiscovery -  eDiscovery tools aren't able to perform 'complete' searches on them
  • When deleting emails (as many organizations do to prevent them from being subpoenaed for litigation) if those emails are on a PST file, they can often be forgotten

And using Outlook to open the PST for eDiscovery has a couple of major problems:

  • You’ll contaminate the file: Outlook changes PST files when it uses them. So, your ‘evidence’ loses its electronic fingerprint (i.e. metadata)
  • You’ll waste a lot of time. Outlook is slow, and it can’t search email attachments. 
  • You can’t search through emails belonging to other profiles - you’ll have to sign in to one account, search, then sign out. And repeat the process with the next account
  • You can’t do the real work of ediscovery because Outlook doesn’t let you tag, redact, and ‘produce’ emails

If not Outlook, then what?

There are many apps out there that handle email ediscovery. The problem is most of them are complicated to use or don’t have the features you need. 

For example, Google Desktop can help you search files, emails, and attachments. But its search options are limited. Microsoft Exchange Server can handle basic ediscovery. But it’s not designed to work with PST files. DtSearch Desktop has a powerful search feature. But it uses command line syntax. Which means you need a background in something like MS-DOS. Your best option? Use an eDiscovery system that automatically reads PSTs - like GoldFynch.