Backup Schedules


Can anyone explain how the schedule works for backups.
I have a client set to backup every 24hrs. First backup ran on time and took 20-30 min then the next backup only started 24hrs after the first backup completed so the backup schedule window is slowly changing each time it runs. Is there a way to set it to run at 12am every day no matter how long each backup takes?

I guess you could combine a lower backup interval with a backup window settings. In your case e.g. an interval every 20h combined with a backup window of 1-7/0-6.