Recently I am adding a folder under Outlook, .contacts as follows “the file so that changes to the file will be reflected in your item”

Recently, when running up Outlook 2010, I am adding a folder under "Outlook", ".contacts" with the following name. " the file so that changes to the file will be reflected in your item." There is no content in the folder, sometimes I can delete the folder and sometimes I cannot. Has anyone experienced a similar problem??