The Microsoft Outlook PST file contains all the data for your inbox. If you have more than one email account within Outlook, you will also have multiple PST files. You may well find yourself having to merge those multiple PST files to create a unified account.

But how do you merge multiple Outlook PST files?

Why Do You Need to Combine Outlook PST Files?

Before we begin, the first question that arises is why would you want to combine multiple Outlook PST files? There are several instances where combining existing PST files into a new data file is the best course of action:

  • Merging multiple old accounts
  • Combining work and social accounts
  • Creating backups of existing accounts
  • Receiving files from a team or family member
  • Migrating to a different service or exchange

That is just a handful of reasons why you might merge PST files. We're sure you can think of more use cases.

1. Combine Outlook PST Files Within Outlook

You can combine multiple Outlook PST (an acronym for Personal Storage Table) files within Outlook. It is a quick task that works with all versions of Outlook from 2007 up to the current time. Thankfully, it's quite easy to do because of a two-stage process.

First, you create a brand-new blank PST file. Then import your existing PST files. Here's how it works.

  1. Select your Home tab, then New Email > More Items > Outlook Data File. Give your blank data file a name and save it.
    Outlook Data File Options
  2. Now, head to File > Open & Export > Import/Export > Import from another program or file.
  3. On the next screen, select Outlook Data File (.pst).
  4. Browse to the PST file you want to import. You now have the option to replace duplicate files, allow the creation of duplicates, or refuse the import of duplicate files. For simplicity, choose Do not import duplicates.
    outlook import data file pst merge
  5. Once the import is completed, you can start the process again to import as many PST files as you want into a single new PST file.

If you're performing the steps for the first time, please remember that you need the password for each PST file you are importing. If you somehow forget the password, you should consider reading our guide on recovering your Microsoft Outlook password.

Moreover, the options for importing a file depend on the file type. For instance, if you're importing a file that is nearly identical to the current file, you need to select Replace duplicates with items imported.

2. Merge PST Files

Merge PST Files is a free tool that you can use to merge multiple PST files simultaneously. When you manually merge PSTs in the above section, you can choose all of your files. This tool uses the same process, but in addition, you get some special features in Merge PST Files.

For instance, Merge PST Files lets you filter the PST merge by folder type, such as only importing contacts or calendar folders from different PST files.

A good thing is that it's free for non-commercial use. However, it will not run in a domain environment. That is because Merge PST Files is a product developed by ReliefJet Essentials, which is a premium Outlook management tool.

Download: Merge PST Files for Windows (Free)

3. ReliefJet Essentials for Microsoft Outlook

Merge multiple Outlook PST files.

From the free tool to the premium tool, what's the difference? Well, ReliefJet Essentials for Microsoft Outlook packs in all the functionality of the free Merge PST Files program, but you also get an extensive range of additional Outlook tools, too.

For example, ReliefJet Essentials allows you to:

  • Import and export any Outlook item
  • Export your contacts into vCard format
  • Find, remove, or move duplicate Outlook items and attachments, with reporting on any duplicates
  • Extract email addresses and URLs from email message headers and text

And a massive list of extra tools, too. This is alongside the ability to merge or join multiple PST files simultaneously. As far as tools go, ReliefJet Essentials certainly packs in more than most. The Premium version retails for $49.95 for a single system, including every ReliefJet Essential utility.

However, they also offer a Single Utility license for $19.95. The Single Utility license lets you install a single utility—in this case, PST Merge—on your system.

Download: Relief Jet Essentials for Windows (Free) | Windows ($19.95 Single Utility) | Windows ($49.95 Personal License)

4. Datavare Outlook PST Merge

Datavare is a freemium Outlook PST merge tool. The free version comes with one significant limitation: you can only merge two PST files simultaneously. In that, the free version is similar to merging your PST manually or using the free Merge PST Files tool above.

The premium license comes with a few PST merge perks, most notably the ability to merge more than two PST files simultaneously. Moreover, you can use several large PST files and merge them quickly. Another handy feature is that you can choose various files from each PST file to merge into a new PST file.

Download: Outlook PST Merge for Windows (Free) | Windows ($29 Personal License)

5. Stellar Merge Mailbox for Outlook

stellar merge mail outlook pst merge

Stellar Merge Mailbox for Outlook is another freemium tool for merging or even joining multiple PST files. While the free version only previews the mail body and attachments of merged or joined PST files, the standard version allows you to save the merged PST files.

For a couple of reasons, Stellar stands out among the freemium tools. First, the UI is very easy to use and appears more modern than some of the alternatives. Second, the premium version allows you to join your PSTs rather than just merge them.

Instead of adding entire PST files into a single large new PST, you can add PSTs as a separate folder structure. It's quite handy if you have detailed existing file structures you don't want to lose when creating your new PST. Meanwhile, in case your Outlook data gets corrupted, you can recover data from damaged PST or OST files using the recovery toolbox.

Also, Stellar Merge Mailbox will merge password-protected PST files without requiring a password. You will still need the password to access the files within the new PST, but you can do the merge easily.

Download: Stellar Merge Mailbox for Windows (Free) | Windows ($39 Standard License)

Merging Outlook PSTs Easily

You have different methods for combining your Outlook PST files. The manual option is basic but does the job. It can become time-consuming if you have numerous PST files that need merging.

If you have a vast backlog of PST files to merge, consider one of the premium options. Stellar Merge comes with a decent UI and some handy settings, while ReliefJet Essentials packs everything and more into a single package (albeit, at a slightly higher price).