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Invisible Hard Drive
Wednesday, April 25, 2007

Invisible to Windows, that is.

I have an older machine, a Dell Dimension XPS T550, which is used mainly for testing and troubleshooting. One common use of this machine is as a "data recovery platform". If a user has a failing disk, I plug it into the IDE (ATA) controller of this machine and try to recover as much as possible. This machine is configured with a hard drive as the master drive in the primary IDE controller. This is the boot drive, drive C:. The primary slave position is left open for attaching the drive "to be fixed". The secondary master is a CD drive, and the secondary slave is also open or available. The OS is Windows XP SP2 with all patches applied.

This arrangement has worked well for several years, and I have installed several dozen different hard drives in the "Primary Slave" IDE position without any problem.

The problem

A couple of months ago I attached a Seagate hard drive (80 GB capacity, model ST380021A) and was surprised to discover that the drive was not visible in Windows Explorer, nor in Disk Management. It was seen by the BIOS, however, and it was known to work in other systems just fine.

I stumbled upon a solution in that case, and went on to other things. Today the problem cropped up again, so I decided to document it here.

Today I attached another drive (Seagate Barracuda model ST3120023A, 120 GB) as the primary slave drive, but the drive was visible neither in Windows Explorer (fig. 1), nor in Disk Management (fig. 2). Drive E: is another hard drive that was attached to the Secondary Slave controller during this.

Fig. 1 - No sign of new drive in Explorer

Figure 1 - no trace of the new drive.

Fig. 2 - No sign of new drive in Disk Management

Figure 2 - not in Disk Management either.

The drive was known to be a good drive, formatted NTFS, and tested on the another system. It was also recognized correctly in the BIOS. The obvious remedies - checking for loose cables, rebooting, etc. - did not lead to success. The size of the drive (120 GB) was not the problem either, because drive E: was also the same size, and working fine.

The drive (model ST3120023A) was not visible in Device Manager either (fig. 3).

Fig. 3 - Not in Device Manager

Figure 3 - and not even in Device Manager.

The solution

The solution in this case turned out to be the same as a few months ago with the 80 GB drive.

I opened Device Manager and selected "Action" -> "Scan for Hardware Changes" (see fig. 4), and after a pause of about 5 seconds, a small notification window near the system tray announced that a new hard drive had been detected, and was ready to use!

Fig. 4 - Scanning for changes

Figure 4 - Scanning for changes in Device Manager.

Another look at Device Manager confirmed that the new drive (ST3120023A) was now present there.

Fig. 5 - New drive has been found

Figure 5 - Drive now present in Device Manager.

Scanning for hardware changes is supposed to run automatically when the system starts, or when a new device is plugged in, but in this case the system failed to identify or find the new drive. A manual scan resulted in the device being located and installed correctly.

Fig. 6 - New drive in Disk Management

Figure 6 - Drive now present in Disk Management.

Fig. 7 - Also in Windows Explorer

Figure 7 - Also in Windows Explorer.


This solution has now worked with two different drives, and yet for the majority of them it is not needed because the drives are identified automatically by Windows on startup.

Here is what I have observed so far, mainly from experimentaion with the Seagate 80 GB drive (model ST380021A):

(1) When the drive is connected to the Primary IDE controller as the slave drive, and the system restarted, the drive is seen in the Bios but not in Windows. It can be made visible in Windows each time by using the above method (of scanning for it in Device Manager).

(2) Once the drive is visible in Windows, and the system is then rebooted, it disappears again until the scan for new hardware is done again.

(3) Other drives, when connected to the same controller, are visible from Windows each time with no problem. The only common thread seems to be that both "failing" drives are made by Seagate. But the sample of invisible drives is too small to draw firm conclusions. Also, other Seagate drives are recognized correctly.

(4) If the failing drive is connected to the Secondary Slave controller, then it is recognized correctly by Windows. A reboot confirms that it is recognized again.

The main conclusion one can draw is that if certain (Seagate only?) drives are connected to the Primary Slave Controller, then Windows fails to find them on startup, but a "Scan for hardware" in Device Manager makes them visible to Windows again. Possibly this is a flaw in the Bios. It could also be a bug in Windows.

(in order from older to newest)

"Thanks for this little run though. I was trying to get windows to see my 30GB Seagate drive and it was doing the same thing. One quick manual scan later I'm in business."

Aug. 22, 2007, 6:33 PM by Dappen

"In chasing down a similar problem I found this blog. I am having exactly the same problem under Vista Ultimate with a Seagate ST360021A as a slave on the Primary controller. If I rescan, it appears. After a reboot, invisible... Mine is a Dell Dimension 8200, BTW. Thanks for the workaround!"

Sep. 7, 2007, 4:01 PM by Jim S.

"I'm trying to work out the same problem on a friend's old gateway machine. I installed a Seagate ST3600 as a slave on the primary controller. It worked flawlessly for 3 months until recently it began disappearing. It reappeared after doing the manual scan (thanks) but do i have do a manual scan everytime I boot up or is there a way to keep it visible?"

Oct. 19, 2007, 5:49 PM by Lou.

"I know of only two workarounds as yet that don't require a rescan after each reboot: (1) Use something other than the primary IDE slave controller (e.g. use the Secondary slave or master controller) or (2) Get a different hard drive.

Option (1) is, of course, much the simpler."

Oct. 19, 2007, 7:19 PM by rk.

"I have the same exact problem with an IBM drive. I discovered that in Safe Mode, the drive is recognized properly as a primary slave on boot. Hope someone finds a fix for this."

Nov. 5, 2007, 5:25 PM by Freestyler.

"I have the same problem on my Dell XPS 210.

This though is for an HP ATA DVD drive.

I have a dual boot system using Windows XP Pro and Vista Home Premium. The drive is known to the Bios and can be used with no problems on XP. Under vista it is not visible until I do a manual scan.

Any pointers to a permanent solution would be useful."

Dec. 11, 2007, 11:56 AM by mjc.

"Exactly the same problem. Seagate 60Gb - disappears until I scan. It started after an MS update. If I restored the problem went away. It then got updated again and the problem started again. Seagate say they havent heard of this problem."

Apr. 3, 2008, 5:10 AM by MarkR.

"I'm experiencing the same issue but unfortunately this did not fix it. I'm adding a second Seagate Barracuda 250 GB SATA internal hard drive. It is known to the bios. I tried it in two different positions: third IDE slave, and also fourth IDE master. I tried the manual scan both times but still cannot make the new drive visible to Windows XP explorer."

May 24, 2008, 9:11 PM by cjd.

"Problem here also. A 500GB Samsung just disappeared after reformatting. It's visible in 'device manager' but not in 'my computer'. Also visible in bios. I guess I will manage after a long time search, but any clue would be appreciated. Thank You!"

June 1, 2008, 7:09 AM by Doy.

"Is it visible in Disk Management? (i.e. Control Panel -> Admin Tools -> Computer Management -> Disk Management)

If so, you may just need to assign a different drive letter to it (right-click on it in Disk Management and select "Change Drive Letter)."

June 1, 2008, 10:51 PM by rk.

"Thanks, that worked. But all the files are gone. The problem is that I had 3 HD's on my pc, then attached another one (80 gb) from an internet cafe. It looked fine with seagate hd-tools and I even formatted it with windows xp, but when I try to install xp I ended up with many problems. I have 3 HD's, one seagate 750gb, one seagate 300GB and one samsung 500GB. The machine would not even start any more when I tried to restart after hanging when install xp on the 80GB disk,  but I managed to reformat and install on the 300GB. I disconnected the 80GB first of course, and now it works again, but the files on the 500GB samsung have turned invisible (unknown filesystem?). The system also say it is "raw". Well, I will try some recovery programs and see if that works."

June 2, 2008, 12:50 AM by Doy.

"I have had the most luck with GetDataBack for data recovery. The link to download the free trial version is Do test with the trial version before buying, it at least shows you what can be recovered. Note there are separate versions of GetDataBack for NTFS and FAT, depending on your disk format.

Another reason for the problem you're having may be that your disk was encrypted. Reinstalling Windows can certainly make it inaccessible unless you take precautions to save the encryption key."

June 2, 2008, 9:30 AM by rk.

"I have a similar problem on my Dell Dimension 5100 running XP Pro. Device Manager sees Hitachi 165GB HDD that's connected on IDE master but the Disk Manager doesn't see it even after doing manual rescan. Flashing the latest BIOS and updating chipset driver from Dell didn't do the trick.

Any pointers?"

June 10, 2008, 4:44 AM by DF.

"You may want to install XP SP2, or even better, SP3, if you haven't done so already."

June 10, 2008, 6:32 PM by rk.

"Thanks for the suggestion! I didn't know there was a SP3... Just to update, the Hitachi HDD is now visible after reformatting."

June 11, 2008, 5:12 AM by DF.

"Thanks for the update, and glad it's working. How did you reformat if it wasn't visible in Disk Management?"

June 11, 2008, 11:53 AM by rk.

"The information provided by this string has proved very useful and helped to resolve a real problem."

June 14, 2008, 1:40 PM by DA.

"Same problem, not sure of drive manufacturer but this issue appeared after various attempts to fix another issue re Flash not playing on certain websites. System restores made when F drive was visible did not restore F drive to visible in Windows Explorer on a consistent basis.

Although not a permanent fix at least this gives me a simple manual solution to my problem!"

July 26, 2008, 7:15 PM by EB.

"I had a problem similar to this and in the end I had to send my drive to a data recovery company.

Whilst they were helpful at and I got all of my lost data back; I can't help but wonder if I had simply tried this method whether or not I would have had to go through the data recovery process at all!?

Does this method work in all cases of hard drives not being recognised or could it be that my case was different?

Also the hard drive was making a clicking noise, is this a Windows problem I wonder - maybe the operating system was trying to read it and failing over and over again. I'm not sure either way but I wish that I had read this article first : ( "

Oct. 4, 2008, 8:44 AM by CS.

"Note for CS, or anyone else with a similar problem:

The method I described above is for a certain special case, and not the most common reason that a drive may be invisible. Much more common are other reasons, such as loose cables, improperly set jumpers, and even failed hard drives.

With the symptoms mentioned by CS, clicking noise etc., hardware failure of the disk is most likely the cause. I am glad you were able to get your files recovered. Regular backups of important files to another disk are a must to avoid this predicament."

Oct. 14, 2008, 3:05 PM by rk.

"Thanks for the reply, I got my hard drive back in the end and have attempted what you have suggested here. You are quite right, in some circumstances it doesn't help, and cannot fix your problem, however, it is good that some real advice on this topic has reached the net.

If you have a problem with your hard drive and can't fix it yourself I cannot recommend this company enough:"

Jan. 13, 2009, 4:54 AM by CS

"Thank you sooooo much, really does work!!!!"

Jan. 20, 2009, 6:08 AM by Shum

"My second internal drive is lost to my BIOS, not just to Device Manager. I run a Dell 8200 with the A09 version of the Phoenix BIOS installed. What do I do to get the BIOS to 'see' my second internal hard drive?"

Jul. 14, 2009, 2:35 PM by jm

"I had similar problem couple of months ago, tried Getdataback and Testdisk. In the end I had send to send the data to They got all my data back."

Oct. 2, 2009, 5:29 PM by RC

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