Why Does the Hard Drive Light Blink Exactly Every Second?

February 23, 2007 3:21 PM

Why is my (windows) hard drive light blinking every second? I've started in msconfig "diagnostic mode - basic devices and services only" and it still does it . . .

I noticed it was blinking every second - on the second - when I noticed it synched up with the ticking of the clock on the wall.

Then I wondered what was accessing the hard drive every second.

Using the Start -> Run -> msconfig utility, I've started bare-bones and run diagnostic "Disk monitor" and "Process Monitor" (and "TCP View") from the seemingly excellent Sysinternals site.

I've gotten it so Registry, File System, and Process & Thread activity is essentially stopped - but the HDD indicator light keeps blinking. Every second. Tick . . tick . . tick . .

Nothing looks out of the ordinary TCP wise . . . Spyware, malware, virus, etc. scans show it's clean . . . ???

I thought it was spyware but no processes run, no ports are open, no disk activity - just this @#! blinking light . . .
It's a 5-yr old Dell Optiblast or whatever, and afaik the HDD light didn't blink like this before

Thanks very much for any suggestions . . and happy bidding!

posted by petebest to Computers & Internet (7 answers total)

Likely it's just the indexing service trying to make future searches faster, but there are lots of other services that could be doing something.

It could also indicate your drive is going bad, and the IDE controller is busy updating the bad-sectors list; if your drive and BIOS support SMART, check for any unusual messages there.

If you have very limited ram, it could be memory swapping to disk.

If you boot the machine from a linux live-CD, once it reaches idle, do you see the same activity? If yes, then hardware, if no, then there is something in your windows environment is behind it.
posted by nomisxid at 3:59 PM on February 23, 2007

Because you need to defrag ?

If its a 5year old DELL.. (assuming its the original hard drive) you should consider replacing the hard drive. I recently worked on a friends DELL Dimension 2600 that had similar problems and after replacing the drive with a new one, it works smooth like butta'

(come to find out later.. Dimension 2600's had a "known problem" of hard drive failures with a specific make/model of hard drive. Sure enough--when I popped open the case and looked, it was the hard drive in question)..
posted by jmnugent at 4:56 PM on February 23, 2007

Forgive me if this is totally obvious, but did you try SysInternals' FileMon utility? I don't know how it differs from DiskMon (I'm on my Mac right now so I can't test it myself), but I've used FileMon in the past and it'll show you all of the processes that are accessing the disk.
posted by phrayzee at 5:07 PM on February 23, 2007

You probably have a keystroke logger/trojan set to write your keystrokes to the disk every second.
posted by fake at 5:58 PM on February 23, 2007

I've seen this behaviour on completely fresh Windows XP Home SP2 installs that have never been connected to the Net. I never did find out what was doing it.

Ubuntu doesn't do it :-)
posted by flabdablet at 9:06 PM on February 23, 2007

I think the drive light blinking is caused by CD polling. Try turning off Automatic-Insert Notification and/or disable AutoPlay for the CD drive.
posted by Fins at 8:52 PM on February 24, 2007

Ah! That's plausible, and would explain why it happens on some systems and not on others; presumably, if the HD and CD were on separate IDE cables, the HD light wouldn't come on when the CD was polled.
posted by flabdablet at 4:36 AM on February 25, 2007