In Free disk space you can
delete files that you do not need any more (for example old backups) in order
to get more disk space.
You can see here how much space your backup files need right now. Now
you can select how the backup files should be deleted. Either Only so many files until required disc space
is available (interesting for users of the SiDiary USB-Stick) or Delete all backup files.
You can also select the number of
backups that you want to keep. In our example above all backups will be deleted
except the 5 newest.
References