US-based class-action lawsuit experts ‘Hattis & Lukacs’ are inviting those who are affected by reliability issues consistent with SMR-based HDDs. This started with the problem affecting SMR-based Red series. Many NAS users with this HDD found unfixable problems with one of the two models of the WD Red series HDD. The earlier one used CMR, while the latter used SMR drives. WD did not disclose the recording method until the fallout of this problem.