You might have not emails in your Outlook inbox. If you notice, the emails you already have in the inbox are up to a certain date i.e only up to 1 month old emails are in your inbox.
Nothing to worry, nothing got deleted, nothing got corrupted. This is default Outlook setting to show only 1 month old emails in the inbox.
If you want to show older or all emails in your inbox, follow these steps:
1. Click on File -> Account Settings -> Account Settings.
2. Your email account must already be selected. If not select it and click on 'Change' button. (See image below)
3. At bottom-right, where it says 'Mail to keep offline', move the slider there to right to show 3 month old, 6, 12, 24 month old or all emails in your inbox. (See image below)
4. Click Next. Outlook will process your inbox. Wait for a while then click 'Close.
5. Finally, click Finish and Close. You've now all emails in your inbox