Storage hdd lost partition after clean install of Win 10 (didn't disconnect storage hdd

). Ran Testdisk on storage hdd for partition recovery. Analyzed, showed one hdd, correct size. Ran p, folders and files there. q to previous screen, where it shows *bootable drive, thought I followed directions, * wouldn't matter, so confirmed WRITE, pressed enter, y, OK. Rebooted. bootup froze at MB splash screen, pc only booted after disconnecting storage hdd. After booting into Win 10, storage hdd does not show in File Explorer, Disk Manager, or Device Manager. PC will not boot if storage hdd connected. Tried Photorec for file recovery, but storage hdd doesn't show.
Any thoughts on why storage hdd doesn't show up in Win 10 or suggestions on how to access it to copy files off of the hdd?