Safely Delete Files From Elements 3 TB Ext HD?

I use a WD Elements 3 TB External HD for doing system backups, and for saving copies of my photography.  While downloading photos onto my Hard drive, I also save them onto the WD.  I just got a message that the backups did not load; looked to see, and sure enough, the WD Elements is full!  But when I got to looking to see what it is full of, I find that mostly it is full of Data FIles that have been backed up.  It shows thatI have 2.22 TB tied-up in data file backups.  I would like to free up space by deleting the oldest backup, which is 1.23 TB in size.  IS THIS SAFE?

Here is what it shows for date file backups:

11/11/2013 to 2/9/2014  1.23 TB

2/23/2014 to 4/20/2014  716.06 GB

5/4/2014 to 5/18/2014    302.76 GB

It looks to me like it is saving the backups cumulatively.  Do I risk losing data if I delete the 1.23 TB backup?  Thank you for any help with this issue!  I just need to be sure before I hit the delete button.


Deleting data before saving it to a different place will always mean loosing data.

The only way you can delete files is when you have a backup for them.

And a backup means 2 copies in different places! A lot of posters here mistakenly moved data from PC to external drive and think that one copy is a backup. If they have problems with the external then they can loose that data.