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Microsoft Outlook/MS Outlook 2007 Email Backup


Hi Nancy,

I regularly backup my email (.PST) file every few weeks. I noticed that the file size was huge 10Gb. So I deleted 90% of all emails. The file size according to "View Mailbox Size" in Tools/Mailbox Cleanup is now 720Mb. But when I back it up, the PST file is 11Gb. What is going on?

Does MS Outlook append as opposed to create a new backup? Not sure why the backup (.PST) file is not 720Mb as displayed in mailbox size.


Hi Robbie - the pst file contains all OUtlook data including Calendar, Tasks, etc.  The following article will be of interest and there is a link that gives an overview of how to decide what you want backed up.

I hope this helps.


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Nancy Janyszeski


Creating,sending, receiving e-mail, scheduling calendar items, tasks, using the journal, recurring appointments, default settings, Office 2003, Vista, 2007, 2010, 2013.


Vocational School Instructor in the Microsoft Office Suite . I am Microsoft Office User Specialist (MOUS) Master Certified and was certified as a MOUS Authorized Instructor. ICDL certified, Microsoft Office 2010. Instructional design and test writer for Skills Advantage,

Microsoft Master Certified and ICDL certified Microsoft Office 2010

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