Hi @pearson1977 , the life expectancy of an HDD can vary quite a bit, anywhere from 3 to 10 years usually, with the average lifespan usually landing in the middle somewhere. It's actually very rare we get a ZEN MkII back with HDD issues which is a good result since those devices are now 8 to 10 years old depending on date of purchase. But drives will ultimately fail which is why we strongly recommend keeping an up to date backup.
Unfortunately, that isn’t possible. The drive would need to be replaced either by us or by an authorised service partner.
Once replaced, we would also need to assign the correct serial number so the system is properly recognised. That said, as Stephen mentioned, this is not something we see very often in practice, and I suspect will be even less likely going forward, with the OS now stored separately on a more robust SSD.