One of my friend was facing an issue in Mac Outlook 2011. He said that the emails from the Outlook folders get disappeared but he can found those by searching in Outlook 2011.
When he opened the outlook 2011 only the mails that arrived on the same day are visible. All other mails were not there.
I am posting the solution here as it may also work for other users, so let's start:
This is a well-known issue in Mac Outlook 2011 that has appeared with the 14.1.2 update. Don't forget to send feedback to Microsoft when you encounter such kinds of error in Mac Outlook
Possible Resolution
Build a new identity and check whether the issue still persists.
Follow the steps mentioned below to build a new identity
- Close all the running applications
- Check out how much space is available in the hard disk. There must be three times more available on the hard disk than the current size of your identity.
- Create a backup copy of your current identity, for that first open the document folder >> Microsoft User Data >> right click on the Office 2011 identity >> click on Duplicate. It will create a copy of your current identity.
- Now proceed further to rebuild database
- Start Mac Outlook 2011 by holding the Option key.
- Now choose the database and click on Rebuild. After the completion of this process a message will be received "Your database was rebuilt successfully".

- Now you are ready to create a new identity: open Mac Outlook from the dock by holding the Option key. This will open the Microsoft Database Utility >> To add a new identity click on the + sign >> Type a name for the new identity >> Set this identity as the default from the action button

- Close Microsoft Database Utility >> Restart Mac Outlook 2011 and check whether the issue is still occurring
- If yes, then consult with the support team of Microsoft