Open up a command prompt and enter: MSINFO32 -> check the bios mode
Make sure that your PC boots in UEFI mode.Looking through the HP information for the HP ProDesk 600 G1 I didn't see any option for ordering a m.2 SSD more or less a NVMe model. Do you wish to clarify your issue and information? Perhaps you are not posting all of the information about your issue. If the BIOS never detects the m.2 SSD then Windows 10 would not see the m.2 SSD. have a contradiction in posted information.Business PCs, Workstations and Point of Sale Systems.Printer Wireless, Networking & Internet.DesignJet, Large Format Printers & Digital Press.
