How to Delete Old Time Machine Backups
From emails and documents to pictures and videos, there is large amount of data we store on our computers. If you use your Mac computer frequently, you probably save a lot of your work on it. Many people protect their work by using the Time Machine software to backup all their data onto an external hard drive. Whenever you need to free up space on this hard drive, you can erase the backup files.
Connect your Time Machine hard drive to your computer.
Double click on the hard drive icon on the desktop. Make sure you click on the computer's hard drive, not the icon for Time Machine backups.
Click on the "Applications" folder.
Click on Time Machine.
Use the arrows to browse through the backup files stored on Time Machine.
Select the backup that you want to delete.
Click the "Action" menu (the icon that looks like a gear).
Click "Delete All Backups."