Try advanced PST Merger of SysInfoTools to combine multiple Outlook PST files into a single file.

SysInfoTools PST Merge 3 by SysInfoTools Software

SysInfoTools has released a major update of its award winning SysInfoTools PST Merge tool. Latest v3.0 represents our commitment towards providing our users more efficient and effective software for their specific needs. In the latest version of SysInfoTools PST Merge, we have fixed various stability and performance related issues. All the pending bugs have been fixed which were found by our staff and by our valuable customers. This release is also a cumulative update of all minor versions which were released since previous major update. Now the software supports removing duplicate items and excluding deleted items from the newly merged PST file to keep it less in size. It also creates a Log file in text format that contains the information of PST merging process at the location which you have selected earlier for merged PST file. Demo version is available for free to assess its functionality and usefulness.