To add a disc, folder, or file to the list of items that Time Machine shouldn’t back up, click on the plus (+) sign. Time Machine will display a standard Open/Save dialog sheet that lets you browse through the file system. Since this is a standard Finder window, you can use the sidebar for quick access to frequently used locations.
Navigate to the item you want to exclude, click on it to select it, and then click the ‘Exclude’ button. Repeat for each item you want to exclude. When you’re finished, click the ‘Done’ button.
