My hard drive passes the HP startup test but isn’t visible on my PC or in Disk Management. Help

[ID_8252516]

I'm having an issue with my hard drive. It passes the HP startup test, but I can't see it on my PC or in Disk Management. Can you help?

[erico]

Does the laptop boot to Windows?

You have not clearly explained what the problem is.

Try  to rephrase it.

[ID_8252516]

I've 2 ssd installed on my laptop
1 is showing in windows other ssd is showing up in hp diagnostic tests but not showing in windows.
I've seen disk management too.

[erico]

Do you also have an OEM SATA legacy hard disk installed?

If the  second ssd  has not been initialized  and has no drive letter, it will not be seen by the Windows OS.

Is the SSD installed in one of the two M.2 SSD slots?

What are the specifications, brand and model of the second SSD?

It should be an M.2 NVMe PCIe SSD.

Is it your plan to use that second SSD as storage?

You should use the command line DiskPart utility. I explained its use in an article that I authored a few years back.

https://h30434.www3.hp.com/t5/Notebooks-Knowledge-Base/Notebook-SSD-upgrade/ta-p/6898561

Just in case you haven't seen this video from HP Suport.

[ID_8252516]

I've a sata 1tb micron m600 mtf installed in this section of my laptop where you've shown HDD. I've tried some diagnostics on my own
        I've tried it as an external ssd I can access it from there.
        I've tried doing a quick format on NTFS and then inserting it internally. Then I've checked it in disk management and                Disk-part using command prompt. No success there
        Tried and other SSD it was 128 GB in size and it was showing in This PC directly.

[erico]

"sata 1tb micron m600 mtf "

What is the format?

Is it a 2.5" (7mm) SSD?

How about verifying that the SATA drive connector is fully seated.

[ID_8252516]

Format is NTFS
Yes it's 2.5 7mm ssd
Yes Sata drive connector is fully seated. Cause I've tested it with other SSD drive there it was working fine.
I did check if this SSD is okay or not by using Sata to USB cable externally and it worked.

[erico]

Is the volume a  GPT or MBR type?

Check in the BIOS to see if the SATA port is disabled.

[ID_8252516]

Sata port is enabled  
I don't know if it's MBR or GPT my first drive is GPT which I can see and use internally.

[erico]

If your first drive is GPT, that is good.

You can still verify that the M.2 SSD is set up properly.

If you have an external means of connecting the M.2 NVMe SSD to a different PC, try verifying with DiskPart that it is active and that it has a driver letter. 

If not, assign it drive letter Z and then put it back in the laptop.