How to Compress PST Files Manually Outside of Outlook

By Dan Howard

You can ZIP an Outlook PST file using a native Windows command.
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Microsoft Outlook stores your Outlook settings and personal data in a PST archive file. The Outlook application includes functions for compressing and exporting your PST files, but in some cases you may wish to perform the compression manually. To compress a PST file manually, you can open the folder that contains your Outlook PST file and use built-in Windows compression technology to save the file to a ZIP archive.

Exit the Microsoft Outlook application.

Hold the Windows logo key and press "R" to open a run command box. Type "explorer" in the box and press Enter to open a Windows Explorer browser.

Navigate to the c:\Users(username)\AppData\Local\Microsoft\Outlook folder. If you are using Windows XP or earlier, instead navigate to the c:\Documents and Settings(username)\Local Settings\Application Data\Microsoft\Outlook folder. In either case, substitute your Windows user name in place of (username) in the path.

Right-click the PST file that you wish to manually compress.

Click "Send To" in the menu and click "Compressed (zipped) folder." Your PST file will be compressed and saved in a file with the .ZIP extension.