You can merge PST files without excessively increasing file size due to duplicate attachments using manual and technical/software-based methods:
Manual Method (Outlook Built-In Option)
- To create a blank PST in Outlook, select File > Account Settings > Data Files > Add.
- Select File > Open & Export > Import/Export > Import from another application or file > Outlook Data File (.pst).
- Choose Do not import duplicates to avoid receiving duplicate emails and attachments.
- Import each PST individually, every time. Do not import duplicates.
- Pros Free; no other software required.
- Cons Time-consuming, requires Outlook installation and can forget some intricate duplication.
Mailvita Merge PST for Mac - An Automated Method
If you are on macOS or have a lot of PST & Mailvita Merge PST for Mac Tool is significantly more convenient.
- The software can discover and remove duplicate items, reducing large file size growth.
- Combine multiple PST files while keeping the folder hierarchy intact.
- It supports both ANSI and UNICODE PSTs from any Outlook version.
- Keeps attachments secure while preventing duplicate storage.
Steps
- Download and Install the Mailvita Merge PST for Mac application.
- Insert several PST files.
- Select merging mode and turn on the option to exclude duplicates.
- To build a single optimized PST, click the Merge button.