ExOL migration - Managing Outlook PST files


In the past CSCS email users have used archive files (also called pst files) to archive email to help with sorting email and managing quota limits. This has happened less in the past several years as email storage increased from 5GB to 50GB and now 100GB.

Anyone with a pst file added to Outlook will have actions to do to find and reconnect their pst files after their mailbox has been migrated. This is not an activity that CSCS will be able to do for you.


You need to have a medschl or other CSCS mail account

You need to have created pst files in the past


The majority of CSCS users won’t have or need a pst file, this guide is primarily for those with existing pst files eg from archives or closed mailboxes they still want to access the contents

An added pst file may look like an extra mailbox within Outlook, so if you are unsure if you have any pst files added go to File > Account Settings > Account Settings

Then click on Data Files tab, any attached pst files will be shown with a .pst at the end of the location along side your mailbox (which is an .ost file)

What happens to existing PST files during the migration to Exchange Online?

Existing pst files will not be brought over automatically, it will be each individual's responsibility to identify, and add them back into Outlook after their mailbox migration is complete. Please see the guidance below.

What to do in advance of the Exchange Online migration

In advance of being migrated, make a note of the saved location of your pst files. You will need to add them back into Outlook after your mailbox has been migrated.

Where existing PST files are saved

Below are the common locations for where pst files are saved by default, but you may have selected any location of your choosing when they were created. If they are not found in the common locations then within Outlook right click on the folder you are trying to find the location of and select “Open file location” and it will open up the folder where the pst file is saved.

Common save locations:

By default Outlook saves them to: My Documents\Outlook Files\

On newer PCs, the files may be on OneDrive. The full file path would be:  C:\Users\<crsid>\OneDrive - University of Cambridge\Documents\Outlook Files\

For older PCs, the files may be on your Home Drive. The full file path is: \\me-filer1\home$\<crsid>\My Documents\Outlook Files\

The traditional location on Outlook 2013 or older is: C:\Users\<crsid>\App Data\Local\Microsoft\Outlook


How to bring my existing PST files into my new @cam.ac.uk Exchange Online email?

Click on File > Open & Export > Open Outlook Data File

Navigate to the location you noted (or the example locations) in the section above. Select your file and click Open and it will automatically create a folder called “Outlook Data File” in your inbox with the exported content, you can now rename this as you wish.