Three conditions that would prevent a normal giveback operation are the presence of failed disks, ongoing SnapMirror updates, and LUNs mapped with ALUA enabled. Failed disks can cause issues with data integrity and availability, ongoing SnapMirror updates involve data replication which must be completed to ensure consistency, and LUNs with ALUA enabled require specific configurations that might not support a giveback operation. Established NFSv3 and CIFS sessions typically wouldn't prevent a giveback operation.