Outlook on new computer versus old computer

On the new PC, first confirm exactly which Outlook product and experience are in use, then compare how message counts are being displayed.

1. Check which Outlook is installed
   • Open Outlook on the new computer.
   • Select File > Office Account (or Help if Office Account is not shown).
   • Under Product Information, note the Outlook version and whether it says Microsoft 365 or another perpetual version.
   • Select About Outlook if details such as 32-bit vs 64-bit are needed.
   • If the UI does not match classic Outlook and you are on Windows 10/11, it may be new Outlook for Windows instead of classic Outlook.
2. Check how counts are shown in the folder list
   • In new Outlook for Windows, most folders show only the unread count after the folder name by default. To see the total number of messages:
     • Hover over the folder name to see “total messages (unread in parentheses)”, or
     • Right‑click the folder; the first menu item shows “total messages (unread in parentheses)”.
   • Compare these totals with the old PC and mobile devices to confirm whether the discrepancy is only in how unread vs total counts are displayed.
3. Consider known count issues
   • If Outlook for Mac is used anywhere in the setup, there was a known issue where the inbox showed an incorrect unread count that has since been fixed by updates. Ensuring all clients are fully updated helps keep counts consistent.

If the new PC is using new Outlook while the old PC uses classic Outlook, differences in how counts are displayed (unread vs total) are the most likely cause, not the license type (Microsoft 365 vs perpetual).

References:

• What version of Outlook do I have?
• Display the total number of messages in a folder in Outlook
• Inbox shows incorrect number of unread items in Outlook for Mac