Microsoft Outlook includes a useful feature to archive your email. This allows you to remove email stored on a third-party internet email server and move it to an archive file stored on your computer. You can perform the archive process manually or automatically.
Archive Email Before 180 Days for Privacy
If you leave your email stored on a third-party internet email server, you risk losing your privacy. Once email is 180 days old, it is considered “abandoned” under the Electronic Communications Privacy Act (ECPA) of 1986 and the Stored Communications Act (SCA). It is not protected under the privacy rights of the 4th Amendment of the Constitution, in the Bill of Rights, so no search warrant is required for authorities to obtain the contents of your older email messages from the third party.
However, email messages that you store on your own computer, regardless of age, rather than on a third-party email server, are protected by privacy rights, and a search warrant is required. So, to maintain your privacy, you should not store email on a third-party email server for more than 180 days.
Set Up Auto-Archiving in Outlook
You can set up the auto-archiving feature of Outlook to automatically move your email from the email server to your own computer before it is 180 days old. You can choose the settings for the age of the email in days, weeks or months, such as 170 days, 25 weeks or 5 months. Your email messages will be stored in a file with an extension of .PST (Personal Storage Table), using the file name and directory that you choose.
Your mail folder names will be maintained in your archive file. The email archive file and folders can be displayed and accessed in Outlook. You can keep recent email messages, less than 180 days old online, and move messages that are older than 180 days to your archive file. Messages stored in your archive file are private and are only available on your computer. Messages stored online can be accessed from any computer or mobile device, using your user name and password to log in to your email account.
Creating Multiple Email Archive Files
If you have many months or years of stored email messages, you may need a lot of storage space on your computer to store your email archive file. It may grow to many GB in size.
You can create multiple email archive files, rather than using one large archive file. One method is to create an archive file for each calendar year, such as archive2015.pst, archive2014.pst, archive2013.pst, etc. You can store old archive files for record-keeping on a removable USB flash drive or micro SD memory card in a fireproof safe.
For more information on breaking a large email archive file into smaller files, see the Microsoft Support article at https://support.microsoft.com/en-us/kb/982577
Change Registry Key to Ignore Date Modified
Outlook will look at the date sent, date received and date modified for each email, and use the most recent date for time calculations. If the email was modified after it was sent or received, the date modified will affect your email archiving, and you may get unexpected results. Old emails might not be moved to the archive file.
You can add or modify a key in your registry file to tell Outlook to ignore the email modification date so that it will only look at the date sent or date received when archiving. This procedure is described by Microsoft Support at http://support.microsoft.com/kb/2553550.
Warning: be very careful any time you make changes to your registry file, you can harm the functioning of your computer if you make a mistake. Follow procedures exactly or get help from an experienced computer technician or system administrator.
Archive Procedures Vary Based on Outlook Version
Procedures for setting up email archiving vary depending on which version of Outlook you are using. Read the help section of Outlook or go to Microsoft Support for details and help.
Set Up an Email Archive to Preserve Email Records
Email archiving is a useful, free feature of Outlook. Learn how to set it up and use it to keep your older email messages private, by storing them on your computer. Use auto-archiving rather than manual archiving, so it will operate automatically for you. You can choose how often you want it to run, such as once a week. Be sure to backup all of your important files, including your email archive file.