hard drive keeps disappearing

[Zenedge]

just like the title says

sometimes my hard drives appears, and sometimes it doesn't

what could be wrong with this?

is it my power supply or my motherboard or the hard drive itself.   i checked the hard drives in hdd sentinel, and they both say 100% health

i already tried switching the data cables, the slots they're connected to. and i tried the hard drives on another pc, and it worked fine.

my power supply is rated at 500W. so i'm sure this is enough for my system.

 

here's my specs

Intel Pentium G3250

4gb ram

amd hd 5850

 

i have 3 hard drives. 1 always appears, but the other 2 random disappear.

 

[Goodman2265]

They turn off when not in use

[don_svetlio]

RiP drive

[King_Tuna]

Your psu's sata power cable may broken.

[smokincola]

Check your bios, see if you have S.M.A.R.T monitoring enabled on the drive. My motherboard has options for setting sata devices to a 'hot swapable' state, when this is enabled I've found devices can mysteriously 'unmount' themselves.

 

Otherwise, I'd fine myself agreeing that your hard drive could be failing.

[Godlygamer23]

They turn off when not in use

That has nothing to do with it. The drives should still be listed even when the spindle spins down - double clicking on a drive makes it spin back up.

[NumLock21]

Had that problem too, took me years to finally figure it out. No it wasn't the hdds, psu, sata data/power cables, or the sata ports itself. In my case, it was the board's PCI slot, when a card was plugged into that faulty slot, the HDD would randomly appear or disappear and do weird thing with the SATA controllers. Removing the card from that faulty slot and the problem went away.  But then that system was 7 years old, so I upgrade it.