A PST file can contain mail, contacts, appointments and other Outlook items. Before migration, establish which data is actually in it. This guide treats an existing Outlook 2007 installation as a data source, not as a way to set up a current mail account in old software.
Inventory all data files
- In Outlook 2007, open File > Data File Management. The archived Microsoft instructions also describe Tools > Options > Mail Setup > Data Files.
- Record the full path, filename and associated folder name for every PST in use. Include separate archives; copying only the default file can miss older records.
- Distinguish personal folders from an Exchange mailbox. An OST is not an equivalent substitute for a portable PST backup. Clarify server-side data and backup arrangements with the administrator. Do not rename OST to PST.
- List important folders, approximate item counts and required date ranges for later checks. Signatures, account settings and AutoComplete are not automatically fully backed up by copying a PST.
Copy closed files
Exit Outlook and other programs accessing the data files. Close properties windows too. Then copy each inventoried PST with the file manager into a new dated backup folder. Copy, do not move. If a file-in-use message appears, stop and resolve the open access; an incomplete live copy is not a verified backup.
Check filenames and sizes and keep another copy on independent, access-controlled storage. PST files can hold an entire private or business mail archive. Equal file sizes alone do not prove intact content.
Test a working copy
Preserve the backup and make a separate working copy on the local disk of a test computer. Open it as an additional data file in a suitable classic Outlook version. Do not change the default delivery location or immediately import everything into a live mailbox. The opening dialog depends on the target version. Microsoft does not support running an active PST on a network share.
Compare folder structure and inspect older and newer messages, required attachments, contacts and appointments. Account for view filters when comparing counts. Do not execute unknown attachments. Resolve missing data or read errors before migration; never attempt repair on the only original.
Migration limits
Exporting selected folders differs from copying a whole PST. Microsoft notes that folder design properties are not preserved during export. Check the exact destination software too: current Microsoft documentation describes restrictions for PST contacts, calendars and imports in new Outlook. Do not plan solely from the extension.
Start the actual migration only after documenting comparisons. Retain the source system and backup until acceptance. A readable archive does not replace checking account settings, sending and receiving in the eventual destination.