Contact list disappearing from new Outlook app after switching from old Outlook app

Hi Chase Hughes,

Thank you for your feedback regarding the issue with the contact list in Outlook.

Below is a detailed step-by-step guide to help you recover the missing contact list (over 200 contacts) and ensure they are fully synced in the New Outlook:

Step 1: Switch from New Outlook to Classic Outlook to Access Contacts

• In New Outlook, you can follow these steps to switch back to Classic Outlook:

Once you’ve returned to Classic Outlook, you can proceed to access the People/Contacts section to locate and export the contact list as described in the following steps.

• If the toggle is not available, open Classic Outlook from the Start menu by searching for “Outlook” or “Outlook (Classic)” and selecting the older version (Outlook 2016/2019/2021 or Office 365).

Step 2: Export Contacts from Classic Outlook

• Go to File > Open & Export > Import/Export

• Select “Export to a file” → “Comma Separated Values (CSV)”
• Choose the folder containing the contacts (usually “Contacts – This Computer Only” if using IMAP)
• Save the CSV file (e.g., ContactsBackup.csv) and verify its contents using Excel or Notepad

Step 3: Import Contacts into New Outlook (Cloud)

• Reopen New Outlook or access Outlook Web
• Go to the People tab and select Import Contacts

• Choose “From a CSV file”, upload the ContactsBackup.csv file, and begin the import
• Once completed, the contact list will appear in both New Outlook and Outlook Web

Note: If the contact list is a Contact Group, it is recommended to export to a PST file to preserve the group structure.

Step 4: Verify and Clean Up

• Check the contact list in Outlook Web to confirm synchronization
• Delete the outdated 2022 contact list to avoid confusion
• Merge or remove duplicate contacts if necessary
• Keep the CSV/PST file as a backup in case of future data loss

If you need further assistance during the process or encounter any issues, please feel free to reach out for technical support.

If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment". 

Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

I have the same issue as the OP's colleague - I'm running Outlook Classic (Microsoft® Outlook® 2021 MSO (Version 2508 Build 16.0.19127.20082) 64-bit) on Window 10, and need to regain access to the contacts maintained in Outlook for a couple of decades now, but suddenly and invisibly hidden recently by some update or other.

I manage contacts on PST files, and after one or another of the recent updates Outlook shows no contacts on my active PST or on a backup. There should be hundreds there.

The option to switch to Outlook Classic doesn't appear, as I am already using Outlook Classic.

Please let me know any suggestions.