One hdd inaccessible

As a subject said one hdd inaccessible, I don’t have red light at al,l blacking or solid,I have normal two blu light and thread one in birthing mode , power saving, sleep mode…on dash board I can see only one hdd and shares from second hdd goon…volume failure message is showing under bell , one hdd is 4tb (working) other is 3tb(inaccessible) ,everything begin working fine for coupe years and now just stopped. Any suggestion please .

It’s difficult to understand your post. Are you set up as JBOD? You say you can see shares on the second drive? have you tried a 5 second reset? A 40 second reset? what operating system do you have on your computer? Windows 7, Windows 10, something else? Can you see the drives on file explorer?

thanx man for your reply, yes JBOD mode, I tray reset 5 and 40 sec, also swap the slots in ex2 ultra , one of the hdd working in any slot i put but other not, I pulled out faulty one , and connected to my pc like internal hdd , and using program DiskInternal Linux Reader I was able to copy all my data with no problem, after I done formatting, wiping , like ntfs ,and windows 10 reading and copying dose with no problem, than I wipe again and putt back in ex2 ultra , and red light hdd volume failure …im lost

Can you access the dashboard? Can you format the disk from the settings menu?