Question

Which type of warning appear when we opening the database which is not trusted.​

Answer 1

Use the Message Bar    Click Enable Content on the Message Bar. When you choose this option, you may need to repeat the procedure if the database changes.  

Trust the database permanently    Place the database in a trusted location — a folder on a drive or network that you mark as trusted. When you choose this option, you no longer see the Message Bar, and you never have to enable the database content as long as the database remains in the trusted location.

If you do not want to trust the database, ignore or close the Message Bar. When you ignore or close the Message Bar, you can still view the data in the database and use any components in the database that Access has not disabled.