Troubleshoot Missing Personal Contacts in Outlook

When personal contacts disappear from Outlook, a phone or the People view, first determine where the contacts were originally stored. Outlook can display contacts from the Exchange mailbox, local PST files, mobile accounts and other connected services.

Isolation steps

1. Open Outlook on the web for the same Microsoft 365 mailbox and check People. If the contacts are present there, the mailbox data is intact and the issue is likely the desktop/mobile client.
2. Check whether Outlook is using the expected profile and mailbox.
3. Look for additional Contacts folders, Deleted Items and Recover Deleted Items where applicable.
4. If a PST was used previously, confirm that data file is still attached to Outlook.
5. On mobile, confirm the correct work account is signed in and that contact synchronisation is enabled only as required by your organisation.

Do not overwrite the good copy

If one device still has the correct contacts, export or otherwise protect that data before resetting profiles or enabling two-way synchronisation. This avoids propagating an accidental deletion.

For widespread or recent loss, administrators should also check Microsoft 365 service health and mailbox audit/recovery options before rebuilding clients.