Can "Backup Set(s)" Be Safely Deleted?

Just double-checking, so I don’t do something disastrous:

My WD drive:
WD 6TB My Book Desktop External Hard Drive - USB 3.0 - WDBFJK0060HBK-NESN

I have a great deal of stuff saved on it, but it should not be anywhere close to full. However, I’m getting a “not sufficient space” message on auto backups.

OS:
Windows 7

To access backed-up files on my WD drive:

My Book (listed as H:)
OWNER-PC
Backup Set(s)

QUESTION:
Can I safely delete these “Backup Sets” to free up space on my WD My Book drive?

Thanks!

Hi etm42,

Which software or backup tool did you use in your computer for data backup?