Hi,
Which folder did you renamed? Is it a default Outlook folder (like Inbox, Sent Items) or a custom folder?
What type of email account are you using? Exchange, IMAP or POP3?
Can you still see the missing emails if we try to login the web mail interface of your email account?
Have you checked the Deleted Items folder and see whether your emails were moved there? If you are using Exchange account, please also have a look at the 'Recover Deleted Items' option under Folder tab.
In additional, we may try to right click on the folder, select Properties >
General tab > Folder Size button, and see whether the folder size is 0 KB.
Regards,
Steve Fan
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