Synthetic Backup Is Not Supported (code 1531)


A backup plan finishes with the following error: Synthetic full backup is not supported. The selected backup storage ({storage_name}) does not support Synthetic Full backup feature


This error appears in cases when the backup storage or some particular storage class does not support the Synthetic Full backup.

Most often, this error occurs in backup plans with the Forever Forward Incremental schedule, since the Forever Forward Incremental mechanism is based on the Synthetic Full backup.


Make sure your storage provider supports the Synthetic Full backup. You can find the list of storage providers that support the Synthetic Full backup in the Cloud Storage Feature Comparison chapter at

If it comes that the Synthetic Full is not supported for backup storage specified in the backup plan, Forever Forward Incremental backup will not be possible. So, you will need to change the backup storage to the one that supports Synthetic Full.

To do this, proceed as follows:

  1. Sign up or create a new storage account for the storage provider that supports the Synthetic Full backup.
  2. Edit the required backup plan: find it in the plan list and click Edit.
  3. Click Next to proceed to the Select Backup Storage step.
  4. In the list of available storage accounts, select the one that supports the Synthetic Full backup.
  5. Follow the wizard to the Schedule step, then configure the Forever Forward Incremental schedule.
  6. Follow the wizard steps to save the backup plan configuration.

Let the backup plan run according to the specified schedule.