So, one of the drives in a NAS overheated. It wouldn't be recognised by the NAS any more, so I took it out. Access via a USB hard drive dock was/seemed fine, I used that drive to copy to the replacement drive. It didn't seem to overheat, I could put my hand on it and it felt warm, not hot. No weird noises or anything strange. I've installed Seatools for Windows to try to test it for errors, but it won't detect the USB drive. The Western Digital drive testing program does detect it, but doing an extended test will take a LOOOONG time (as in 28 hours LOOONG), and I don't want to bother if Seagate won't accept it if it shows problems with the drive. It's still under warranty. What should I do now? Online searching for overheating all refers to the overheated drive as "damaged" or dead because of the overheating. This didn't die. Can "damage" be assumed? What causes overheating? There doesn't seem to be any cause with the hardware, the replacement in the same bay is normal, as are all of the other drives in the NAS. Fans operating normally.