windows sercver backup problem

[Ish]

Hi

We have an SBS2011 server and are using windows server backup which backups to an external 2TB hard drive. The problem we have is that when the hard drive fills up instead of overwriting the oldest backup all the backups get deleted and the backups start again.

What is causing this as we just want it to overwrite the oldest backups?

 

[Ish]

Thanks. I've changed the setting now so will see how it goes.