What is the best way to combine multiple Outlook data file into one?
It is always to prefer ways which are easy and efficient, I would suggest you try few steps manual methods and if the problem still occurs then the only solution will be using a professional tool.
There are generally 2 steps to combine PST file manually,
- Create a new blank Outlook data file file
• Just Go to Outlook Windows > New Items -> More Items -> Outlook Data File
• Select a location to save the new blank Outlook data file and then name it
• Click OK
- Now combine Outlook data files into the newly created blank data file
• Go to Outlook Windows > File -> Open -> Import
• This step will open the Import-Export Wizard. Choose Import from another program or file > Click Next
• Choose the file type Outlook Data File (.pst) to import from > Click Next > Select Browse to locate the file to be imported
• Select the Do not import duplicates box > click Next > Select folder to Import > Check the Include subfolders and Import items into the same folder in boxes > Click finish
If this method helps then great, or else you can use Stellar Merge Mailbox for Outlook, a great tool which I have personally used by seeing many professionals review and recommendation. This tool can merge multiple PST files at one go and gives 100% integrity results.