MakingĀ folders private provides an extra layer of security for confidential and/or sensitive files in folders that you do not want to share with other people. If you make a folder private, it can't be shared with other people and no one except you can browse it.
To make a folder private, hover over the name of the folder on your My Files page, and click "make private".
To make a folder public again, hover over the name of the folder on your My Files page and click "make public". Please see "What are public folders?" for more info.
PrivateĀ folders appear in red on your My Files page.