[Help!] Windows SSD gets "reboot and select proper boot device" & doesn't show up in Boot Priority!

[hopfulhacker]

I recently did a clean install of High Sierra on my other SSD and it seems my drive that has windows no longer shows up in boot priority in bios and if i try and boot straight off it using the select drive (f12), (what I usually do) it goes to the reboot and select proper boot device. Super frustrating and wondering if my drive has failed?

 

[Going Bald]

Was the other SSD connected when you installed Windows? Did you examine the drive format/partition structure before reformatting and installing Mac OS? More than likely, Windows installer installed the boot files on your spare SSD and installing Mac OS on it destroyed them. Things like this is why I suggest only one drive be connected when installing Windows. You might be able to use the install media to repair the boot on the Windows drive but it is not likely as the partitions will not be there.
Suggest installing Windows on a spare drive and use it to copy over your files from the broken installation.