I recently deleted some old Calendar and Contact folders which I thought I no longer needed. However, it appears that I do. I haven’t emptied my Deleted Items folder in a while so these folders must still be there.

Sometimes, there is an indication that the Deleted Items folder is containing sub folders but when I click on the triangle to expand the Deleted Items folder, it just disappears and doesn’t show anything.

How can I recover them and why is the triangle disappearing?