OS X: Free space on your Time Machine backup drive

Recently I discovered, that my external hard drive for Time Machine backups is slowly running out of space – only ~20 GB left on a 320GB drive.

Searching through the web I did not find any up-to-date help on how to properly remove old backups in order to have more space available. But when trying the most easy and obvious way, I figured out that’s how Apple intended to do it:

1. Connect the Time Machine drive and browse to the folder ending in “.backupdb”
   
    
2. Select all folders (f.eg. < actual year) and move them to the Trash
   
    
3. OS X detects, that you are trying to remove backup folders – thus it’s going to ask you, if you really want to remove the folders from the backup history
   
    
4. Confirm the message, enter your Admin Username and Password
    
5. Wait, until the move process is done (you might hear the drive working, or check the Activity Monitor’s harddrive activity indicator)
   
    
6. Empty the Trash