How to see unread messages in Mail?

Julius N wrote:

Mail indicates unread messages in my inbox:

https://discussions.apple.com/content/attachment/f48bf17c-febe-4d87-bb2c-6d07ad7bbbea

I select the inbox and activate the unread filter:

https://discussions.apple.com/content/attachment/27f1e0b7-0b9f-47a5-a231-4b6d19d1b70d

No messages are shown. How do I see my unread messages? The search textfield is empty.

I'm on Mac OS 10.15.7 Catalina.

Old problem, new problem, what changed?

All Mail in Favorites or selected inBox's ...

Quit Mail, relaunch the Mail.app holding the Shift key down—any difference?

If no resolve you can try Rebuild mailboxes in Mail on Mac - Apple Support

Julius N wrote:

Thank you. Rebuilding the mailbox worked, I can now see the unread emails in my inbox. Relaunching while holding down the shift key did nothing; what was it supposed to do?

Good computing Julius N !