Symantec Backup Exec 12.5 - How to stop disk backups from using all the the disk spac

[OSSMAPhil]

Hi,

We have daily incremental and weekly full backs set.

We have just increased the disk capacity as backups were failing due to not enough disk space.

For some reason, exec keeps creating new backups and using all the available disk space rather than overwriting.

The jobs are set to overwrite. The media is set to not overwrite for 3 weeks, but there are ample backups there that are marked as overwritable but it still creates new ones.

Any ideas please?