The Sidebar in Finder windows is a handy place to store commonly used files and folders. All you have to do is drag an item into the Sidebar for it to appear, and drag it out to make it disappear. You can do the same thing with the disk icons in your Sidebar, too.
For example, if you know that you will never connect to a network server, simply drag the network icon out of the Sidebar, and it disappears in a puff of smoke. If you prefer to see your disks in a different order, drag each one so that it sits in the list exactly where you want it. 
Dragging an icon out of the Sidebar to free up space. You can always add it back later.
Since the items in your Sidebar are aliases to the original, removing them won’t harm any of your files. Your applications, documents, folders and disks are still exactly where you left them.
Let’s say you decide you want to have the Network icon back in your Sidebar. No problem. Here’s what you do:
- Click on the Desktop to make sure the Finder is the active application.
- Choose Finder>Preferences.
- Click the Sidebar icon in the Finder preferences pane.
- Check Network.
If you drag a specific CD, DVD, or hard drive out of the Sidebar, you’ll see a dash instead of a check by that item type in the Show these items in the Sidebar list. Click the dash once to remove all similar items from the Sidebar. Click one more time to add all of the items, including what ever you previously dragged out, back to the Sidebar.
Use the Finder preferences to add items back into your Sidebar.Take a quick look at the Finder preferences image again. You’ll see that there is a dash next to Removable media (such as CDs). That’s because I dragged a specific CD out of my Sidebar. Clicking the dash once will hide all prevent all removable media from showing up in my Sidebar, even though it still appears on my Desktop. Clicking again will tell my Mac to display all mounted CDs in the Sidebar.
- Click the Sidebar icon in the Finder preferences pane.
