hi Damian.
Cause:
A previous incremental backup point failed to write due to insufficient storage space. When the retention policy was triggered, this point could not be merged or deleted.
Solution / Steps:
Check the self-describing file of the backup data. If the data wasn’t successfully written due to storage issues, the UI might still show the backup as successful, but there will be warnings in Alerts that need to be manually checked. Review the backup date and search Alerts for previous backup tasks that had failures or warnings. Locate the failed backup point based on the Alerts information, manually delete it, and rerun the backup. This will allow the retention policy to execute properly.
hope this helps!
