This error can occur when a source volume is mapped on more volume paths, for example, a drive letter and one or more mount point directories. Because TSM uses the volume path to keep track of backup information in its internal backups database, it cannot back up the same volume with a duplicate volume path. See addition information in the error log.
TSM cannot select the volume.
Delete the last snapshots created as they are not managed by TSM. Unmount the duplicate volume path in order to have a single mount point to the same source volume. Restart TSM and retry the operation.