A severe issue with the fourth generation of raptor drives was faulty firmware, which caused the drive to report TLER timeouts after roughly 50 days of continuous operation (precisely 49.71 days counted in milliseconds, which corresponds to the overflow of a 32-bit number). The bug has been present in all models of drives shipped, from their introduction up to late 2009. WDC never admitted the existence of this bug, or officially released a firmware update; however, an update was leaked by a WDC technician and is still readily available through various download sites. The bug was of minor significance for desktop users, but prolonged drive operation in RAID setups could result in mass drive dropouts after 49.71 days, causing maintenance problems and potentially data loss.