Iincremental backup error "failed to build valid list of incremental entries" (4032814)

Full backup using a selection set runs and completes successfully, but subsequent incremental backups using the same selection set fail with error:

"error processing existing directory list"

"failed to build valid list of incremental entries"

"failed to prepare for an incremental backup"

This is usually due to a lack of space to properly build or process an index list.

NetVault Backup uses the specified temporary directory (configured within NetVault Configurator > General > Temporary Directory) on the NetVault server and the client that is being backed up to process indexes of the full backup to find out what data should be backed up in the incremental backup.

There needs to be several GB of free space available for this directory to generate and process the backup list.

The temp space is cleared out immediately after job completion. In certain circumstances a failed backup or aborted backups will result in temp space still being occupied from these jobs.
  

The temp directory can be relocated if required using NetVault Configurator > General > Temporary Directory to specify a different location.

Make sure the full backup on which this incremental is based is not expired or deleted. You can verify this within media management, under the tapes containing the backup. You can also verify it by opening a restore window and checking the full backup is there.