New Windows 10 Installation Not Recognizing HDD.

I currently have a functional Windows 10 64Bit, with SSD for the OS, and two Seagate HHDs for my data.

I am creating a new Windows 10, with a different SSD.
During the new installation, the BIOS sees all three drives and the installation also sees all three drives.

However, after installation, only the SSD (OS) drive is recognized. Both Seagate HDDs are NOT seen in both the File Explorer and the Disk Manager.

What's going on here? Why is the new installation not seeing the two HDDs? How can I solve this issue?

Cheers.

dalchina said:

How are the 2 HDDs configured? RAID? As a storage space? Or as individual and separate drives?

Separate drives on their own data connectors.

dalchina said:

Note that when (re) installing Windows, it's safest not to have other drives accessible.

Yeah I know, I learnt the wrong way, so I don't do that anymore.

dalchina said:

Check that all your Windows partitions have been placed on your system disk and (when you can) that there are none on your data HDDs.

I usually have a dedicated drive for my OS that also has the small system partition.

dalchina said:

- is your installation BIOS/MBR or UEFI/GPT? 32 or 64 bits?

It's MBR and 64 Bits

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idgat said:

Whatever you do just be careful. If Windows "thinks" the drives are not initiated, initiating them arbitrarily will result in loss of all data.
Is there any data on the drives ?

They are both my data drives which I have a backup image of the two drives.
Just finished backing up one drive, going to back up the second, to have much current data backed up.

I just thought of something. I plugged back the drive with the newly installed OS, and decided to do Windows update. After the updates, the two drives came on; I guess the new Windows installation was missing (I guess), generic disk drivers.

So, all is well now. I really appreciate all your help in this matter.
Thanks !!!