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Windows 7: Constant 100% HDD Activity Light

02 Jul 2010   #1

Windows 7 Ultimate
Constant 100% HDD Activity Light

I've searched around various places and I have found different problems with hard disk lights blinking and constant hard disk activity, but I have not found one that matches my exact problem. I have a fairly newish computer, with an Asrock x58 Xtreme 3 motherboard, Intel Core i7 930, and an OCZ Vertex LE SSD. When I first installed Windows, I disabled things like auto disk defragmentation, prefetch or superfetch (whichever the one is that most people disable when they have SSDs, I don't exactly remember), and so on. After this, my hard drive light would blink probably once per second.

I'm not sure what happened, I don't even know WHEN it happened, but my hard drive light started being on constantly. 100% of the time. The light doesn't even blink, it's just on solid. I went into Resource Monitor to try to track down which program was doing it. Sadly, the process that looked like it was the problem was "System". It is constantly reading and writing about 87,000,000 Bytes per second 100% of the time every day. I am worried this is going to ruin my SSD, and I would really like to figure out what is causing this problem. This screenshot shows my Resource Monitor. I ran a full computer scan with AVG and it didn't seem to find any problems. I was hoping someone could help me troubleshoot this. It didn't used to be like this. Thanks.

Attached Thumbnails
Constant 100% HDD Activity Light-diskactivity.png  
My System SpecsSystem Spec
02 Jul 2010   #2

Windows 7 Home Premium

No answer but have you seen this topic?
Your description of "System" being the culprit sounds similar.

Something is making ~15GB of .TMP files every few hours

My System SpecsSystem Spec
02 Jul 2010   #3

64-Bit Windows 7 - Home Premium Edition; Linux Mint 11

SuperFetch or search indexing would likely be the culprit. Try turning one or both of them off.

You also wanna try this program to monitor your HDD activity and find out the culprit:
Process Monitor
My System SpecsSystem Spec

02 Jul 2010   #4

Windows 7 32bit, Windows XP Pro., Ubunto.

Hard drive activity sometime is caused by malware. If you are connected to the internet you should check whether your modem or router activity lights are also flashing. Your machine could be acting as a server to relay malware. If you have scanned with an updated AVG, also scan using the rootkit scanner, then I suggest you download Malwarebytes. When you get a malware problem you need to check it out with at least two separate types of scanner if not three! It could of course be a propriety defragger or something scheduled working in the background. Go to task manager and check what services are running.
My System SpecsSystem Spec
02 Jul 2010   #5

Windows 7 Ultimate x64 Service Pack 1

Indeed, this could be a HDD Controller chip issue to...

I know from unfortunate experience, that a constant activity light, and frequently random HDD accesses indicate the early symptoms of controller failure - which in most cases requires a new mobo...

And that's bad!

Try going into the Event Viewer in the Administrative section of the Control Panel. Click on System in the left panel, and look for errors - if the controller is the culprit, it should say something like "The device /HardDisk0/ encountered a controller I/O error."

Hope this is some help to you.
My System SpecsSystem Spec
02 Jul 2010   #6

Windows 7 Ultimate

This is very very weird, but when I got up this morning the light was back to its normal intermittent blinking. It was not on solid. I am very confused, because it was pretty much solid for 2 or 3 days straight. I checked my Event Viewer like you said, and I didn't see any errors that were complaining about HardDisk0 or any other hard disk for that matter, so I guess I'm at a loss. I'm just going to cross my fingers and hope it doesn't start happening again. RMAing a motherboard is a pain. Thanks for all of your suggestions.
My System SpecsSystem Spec
02 Jul 2010   #7

Windows 7 x64 Ultimate

Well something like turning the indexing of the drive on if it was off could cause that. It's one of the reasons a lot of people turn it off when they do a new install. The first few days after a new install the HD is going off CONSTANTLY.

So if you had maybe just turned indexing back on.. Or AV programs can caus it, though a full HD scan on an SSD is generally pretty fast, not lasting hours over several days :/
My System SpecsSystem Spec
18 Oct 2016   #8

Windows 7 x64 Professional
How did this resolve???

Hello FJimbo ~ Yes, I'm looking at the exact same problem and wondering how your issue finally resolved.


Thank you!
My System SpecsSystem Spec
22 Dec 2018   #9

7 pro 32 bit
Cured HDD light on constantly

I just updated my IDE drive Vista installation to Windows 7 on a blank SATA drive (Intel Mobo DP965LT). From then on the HDD light stayed on constantly- never a flicker even. I'd removed the old IDE drive not thinking it was needed. Wrong! After much trial and error I refitted the IDE drive (still set to master) and reset the boot order in BIOS to boot from the SATA drive. BINGO! HDD light now working as it is supposed to. I can only surmise there was something on the IDE drive that was needed for the HDD light to function.
My System SpecsSystem Spec

 Constant 100% HDD Activity Light

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