my data file is a pst file - how to sync contacts?

To sync contacts (and other items) from a local .pst file into a Microsoft 365 mailbox, import the .pst into the Microsoft 365 account in Outlook so the data is stored in the cloud mailbox instead of only in the local data file.

Use classic Outlook on Windows and follow these steps:

1. Open Outlook (classic desktop app).
2. Select File on the ribbon.
3. Choose Open & Export > Import/Export.
4. In the wizard, select Import from another program or file, then Next.
5. Select Outlook Data File (.pst), then Next.
6. Browse to the .pst file that contains the contacts (and any other data) to move.
7. Under Options, choose how to handle duplicates (for example, Replace duplicates with items imported or Do not import duplicates), then select Next.
8. When prompted for the destination, select the Microsoft 365 mailbox (not the local data file). This ensures the items go into the Microsoft 365 data store:
   • To merge into the standard folders, choose the Microsoft 365 mailbox root and leave Import items into the same folder in: selected.
   • Alternatively, select Import items into the current folder if importing into a specific folder.
9. Select Finish and wait for the import to complete.

Once imported into the Microsoft 365 mailbox, Outlook and other connected clients (including mobile and Outlook on the web) will sync those contacts and other items from the cloud mailbox rather than from the local .pst.

If only a few contacts or items are needed, instead of a full import, open the .pst and drag items into the Microsoft 365 Contacts (or other) folders:

1. File > Open & Export > Open Outlook Data File.
2. Browse to and open the .pst.
3. In the folder list, drag contacts (or other items) from the .pst folders into the corresponding folders under the Microsoft 365 mailbox.

References:

• Import email, contacts, and calendar from an Outlook .pst file
• Move your old email, calendars, and contacts to Microsoft 365