A user’s Outlook account saves all the mailbox data in a PST file. The ‘data’ here represents all the information in emails, calendars, contacts, etc. PST is the portable storage table generated as a .pst extension. In this article, we will discuss the need and ways to merge PST files easily.

What are the differences between OST and PST files?

1- OST files are only compatible with the Exchange server. On the other hand, PST files work efficiently with various services.

2- Moreover, OST files are generated automatically as a folder in users’ devices by Microsoft Outlook or Exchange server. While, users create PST files to store details from emails, contacts, calendars, journals, notes, etc., from their mailbox.

3- Then again, working with OST files is much easier as users can make changes in .ost files without being connected to the network. But, PST files require a connection to modify data in them.

Reasons to merge PST files.

Some of the most prominent reasons to merge PST files include:-

  • Sometimes, it is harder to share multiple files with someone in one go. And, merging PST files can make it simpler to transfer a single file.
  • Managing and handling PST files become much less complicated after merging.
  • Users with more than one account in MS Outlook would like to merge all the accounts.
  • Usually, users do not appreciate having to open multiple files over and over again. So, after merging the PST file’s data, the users will have to open only a single file to access their data.
  • Generally, users like to backup their critical data. Another reason to merge PST files is to avoid accidental deletion of the information.

The chances of users merging PST files are growing higher with each new version of MS Outlook. In the previous version of MS Outlook, the PST file storage limit was 20 GB. However, Microsoft decided to change it to 50 GB in the newer versions, such as Outlook 2010, 2013, 2016, 2019, and Office 365. 

What are the methods to join/merge PST files?

I- The manual method- Includes two main steps. 

a. Generate a new PST file.

b. Import all the other PST files’ data in the new file.

II- PST Merge Tool- A professional software to merge PST files automatically.

A step-by-step guide {Manual Method}:-

Step 1:- Create a PST file.

  • Launce MS Outlook and select ‘New items.’
  • Click on ‘More items.’
  • Choose ‘Outlook data file’ and mention the location you would like to store the file.
  • Assign your PST file a name and click on ‘Ok.’

Step 2:- Now import the PST files.

  • Start MS Outlook and then click on File tab >> Open >> Import.
  • Then, in Import and Export Wizard dropdown, select the Import from another program or file title.
  • After that, Click on Next and pick the file type to import.
  • Now, select Outlook Data File(.pst) >> Next >> Browse >> file to import.
  • Then, Mark the Do not import Duplicates option >> Next >> Choose the “folder to import from.”
  • Check the Include subfolders and Import items into the same folder, then Finish.

Pros and cons of the manual method:-


1- Cost-efficient.

2- This method works best for a small number of PST files.

3- There is no need to spend time looking for the perfect software.


1- It’s Ineffective for a massive count of files.

2- Time-consuming and tedious process.

The Third-party software might cost you a bit but does the job quickly and efficiently. As, it fights all the limitations of the manual method to merge PST files users encounter.

Professional Software(PST Merge Tool)

Many MS Outlook users fancy a proficient software application to merge PST files when they don’t wish to settle on the manual method considering its lengthy procedure. Because, this kind of expert software is an ideal arrangement that merges PST files into a separate PST file in a short duration of time. 

Additionally, there is an adequate number of this software present in the market. It ensures to cater to the merging needs of PST files efficiently. However, not all of the available options in the extensive collection are up to the mark. Some of these software tools have marked their presence. Hence, I would advise you to choose wisely.

A few of the advantages that most of the PST Merging tools in the market have in common are:-

  • It merges multiple PST files at a time.
  • Compared to the manual method, it takes no time to merge PST files.
  • Besides, it is able to merge PST files regardless of their size.
  • Compatible with almost all the Windows OS and MS Outlook variants.
  • Lastly, it let’s users examine the software by providing a costless trial run.

Note:- This trial run merges only about the first 50 items. This number depends upon the service provider. Some let you merge 50 items, some only ten items.

How much do these tools cost?

Generally, the cost of this sort of tool can range from $20 to $150. It depends upon the licensing you’re trying to buy. Usually, there are personal, standard, and technical licenses. A personal license costs the least, while technical the most among the three. Personal license is suited for individual or home users, standard license for organizations and technology-related companies set up in various locations.

If you have any questions regarding the subject, feel free to comment.

Also read:- Download Office 365 Emails to Outlook.

Top software to merge PST files(In my opinion)

Stellar Merge Mailbox for Outlook 

An incredible asset to merge different Outlook PST files into a solitary PST. By joining PSTs, you get a structured hierarchy in the PST document. It offers the feature to merge all or select Emails, Contacts, Notes, Calendars, To-Do, and Task folders. You can use PSTs from various Outlook versions without worrying about data corruption or loss.

  • Merges or joins PST files with 100% data accuracy. 
  • Furthermore, it recovers new or existing PST, Outlook profile, Office 365, and Exchange.
  • Finally, it works like a charm with Outlook 2019, 2016, 2013, 2010, 2007, and other variants.

I hope this article helped! Cheers!