Follow the below steps to merge multiple PST files into one file
Download the DRS PST Merge Tool. Install the application and run it as administrator.
Click the Add File button to add the desired file. You can also add a complete folder containing PST files by pressing the Add Folder button. In case of adding an undesired file, click on the Remove or Remove All button.
After you add the files, they will appear in the list. Click on the Next button to proceed further.
You see the file preview in the tree structure in the left pane. Tick on the desired mailbox items you want to merge.
Now, you will see two options: Join PST and Merge PST. You can opt for any one option as per your requirement.
Follow the Below Steps to Join PST Files into One
Tick the Join PST option to join all the selected Outlook PST files.
After that, select the Outlook PST item you want to merge. Tick Mail, Calendar, Tasks, Contacts, Journal, and Notes.
Tick the Specify Date Range option and define an appropriate date range. Click on the Add button to add the date range entry and Remove if you want to remove the entry. Press Next to proceed further.
Select the Join in New PST File option to add all the selected files in a new file.
Otherwise, mark the Join in Existing PST option if you want to add all the data in an existing PST file. Click on the Destination button to define the saving location.
Now, choose the remaining tool options like Apply password, Remove duplicates, and Remove Attachments. Hit the Join button to join all the selected Outlook PST files.
The application processes the request. The time taken in the process will depend upon the size of the selected files. Click Stop if you want to quit the process.
After successfully Joining Outlook PST files, you will see a pop-up of the process completion. Press OK to close the pop-up wizard.
Below are the steps to Merge PST File into a Single File
Select the Merge PST option to merge multiple PST files into one. Press Next.
Tick the Outlook PST mailbox items you want to merge: Mail, Calendar, Tasks, Contacts, Journal, and Notes.
After that, mark the Specify Date Range option for selective file merging. Define the appropriate date range and click Add to add the date range. Also, you can click Remove to delete an incorrect entry. Press the Next button.
Now, opt for the Merge in New PST option for merging multiple PST files into a new file.
Alternatively, you can opt for the Merge in Existing PST option. It allows you to save the output data in an existing PST file. Click Destination to define the saving location.
After that, specify the remaining options: Apply Password, Remove Duplicates, and Remove Attachments. Click on the Merge button to start PST merging.
The software will process your request to merge the selected PST files. Click Stop to quit the running process.
At last, you will see a pop-up showing the completion of merging. Click OK to close it.