Windows 7: AHCI mode stopped reconizing Hard Drive

Yesterday my Wife's laptop stopped booting for her so I started to troubleshoot it.

What I've discovered is:

- If the BIOS setting for the hard drive controller is AHCI it will not recognize the drive. (This was the default setting in the BIOS)

- If changed to IDE mode it recognizes the drive but come up with an "No operating system detected" message.

- If the hard drive is installed in a second lap top it works fine.

- If another hard drive is installed it works fine in AHCI mode.

Only the combination of the original hard drive and the original lap top wont work.

Am I missing something?

Sean

You may want to see if any bios updates are available for it.
IDE mode will never see the AHCI data it can be reformatted in ide mode and then have windows installed on it.

Here is a thought though.
completely power down the laptop remove the battery and everything.
Let it sit for an hour or so like that.
Plug everything back in and give it another try in ahci mode.
This only has a small chance of working but it's worth trying.

I agree with most of your comments, but chances are that misunderstood some of it..

Are you sure that "IDE mode will never see the AHCI data"? As long as the BIOS boot sequence configured correctly for the AHCI/IDE modes, Windows should boot up just fine.

I try, but I seem to suck at explaining things sometimes.

The answer so far as I know, is that without being able to boot in the first place, you can't make the switch between and have windows bootable.
IF you had access to windows on that drive you could use a method like this.
Guide Guide to enable IDE/AHCI without reinstalling

Though I have heard it meets with varying levels of success.

You're doing just fine Magus... thanks...

In general, I agree with you again, but switching between storage type in the BIOS does allow Windows to boot sometimes. If you recall, in this BIOS issue:

BIOS battery backup issue...

I had some problems with the BIOS/CMOS settings lost when the power is killed overnight. In relation to the storage type...

Due to this issue, the storage type has changed twice, once from AHCI to IDE. Yes, there was "no bootable" device found error message in the BIOS screen; however, once the boot order was configured correctly, Windows has booted just fine. Windows did load new device drivers and required a reboot, but otherwise worked just fine.

After Layback Bear's solution to this issue, the IDE had been changed to AHCI in the BIOS and the correct boot order had been configured. Windows did boot just fine again and this time, it did not complain about reboot and storage type has been verified as AHCI.

I've seen the registry trick for forcing storage type change in Windows 7, but forgot to do it prior to changing the BIOS settings. Maybe when Windows changed to IDE, it did do the registry trick on its own.

Maybe my machine was just lucky, but would be nice to know why on some machines it happens, while on others it does not...

My opinion. The reason the registry changes are made is to force Windows to load AHCI drivers after the bios change is made. But, if AHCI drivers have already been installed, Windows will boot, but has to load those drivers, requiring a reboot. If you have installed in IDE mode but installed IRST, they contain IaStor, Intel's AHCI driver. Therefore the drivers are in the system, just not being used.

northernsmith, What are the system specs for the laptop including manufacturer and complete model number? Also, what brand of hard drive are we talking about?

To me, this seems like an unusual problem. To be safe, I would recommend copying all personal info from the hard drive while attached to another machine.

I tried the registry edit, no go doesn't change any thing.

The laptop is an ACER 5820TG-6406 and the drive is a Toshiba model MK6465GSX 640GB

I'm going to clone the drive so I don't loose any thing.


It's a very weird problem.

Sean

Try to download and run the hard drive diagnostic test for the drive. If that passes, I would look for updated BIOS, AHCI drivers and chipset drivers from Acer. Failing those, I'm at a loss. I don't believe I've ever come accross this problem before. Obviously either the computer or the hard drive is at fault, but determining which in this case may be a challange.

If nono of that works, try setting bios to IDE mode, go to the boot tab and set the DVD as 1st boot device and the hard drive as second. Boot into the Repair or installation DVD and follow this tutorial. You may have to run it 3 times to get it to work,with an attempt to boot in between each. See if this works for you.

Startup Repair