Let me know which you have so I can confirm your slot is active! HP ProBook 450 G2 SSD Upgrade - HP Support Community

HP ProBook 450 G2 has a dedicated M.2 slot, but compatibility is highly specific regarding the drive's physical size and interface. Key Compatibility Specifications Interface Type drives are supported. : This model does not support NVMe/PCIe SSDs

While modern "M.2" often implies high-speed NVMe, the ProBook 450 G2 was released during a transition period.

If you are unsure about the M.2 availability, swapping the main 2.5-inch hard drive for a standard SSD remains the safest and most reliable way to speed up this laptop. However, for those determined to utilize the M.2 socket, sticking strictly to SATA protocols is the only path to success.

: The M.2 slot is generally not available or functional on models equipped with Intel Celeron or Pentium processors.