Hello everyone, Perhaps someone has encountered this before. I have a Windows Server 2016 Essentials in my spare room assembled out of old parts. Nothing fancy, an old AMD APU I was not using and a pair of old 150gb WD Raptors for OS drive. I had some old laptop HDDs for various backups and recently discovered one of these HDDs had bad sectors. So I removed that drive and replaced it with a different HDD. This is the point where I see things get weird. I have never seen this particular problem in all my years of IT'ing. Any new or additional HDD I plug into this PC will not show up in the disk management window of computer management. They also do not show when using the DiskPart command line tool. They DO show in the BIOS and do show in device manager. If I use a tool like HWInfo, the HDDs are listed there and I can interrogate the SMART status of each of these HDDs. I can see which port they are connected to and read temperatures and such. Any working new or additional HDD that I add to the system has the same problem. MBR, GPT and a pair of Storage Spaced HDDs have the same problem. I have researched this via Internet and have found a few people with the same issue, but no resolution. As far as I can see it is not a driver problem. It seems like the OS does not want to add any new HDDs. The HDDs in question work without issue in other PCs. Anyone got any ideas on how to fix this? Thanks. Aus.