[SimonLam]

To all user community who may face the same issue as me:

Requirement:
1. Windows 7 Ultimate 64bit
2. Intel X25M G2 SSD
3. You have either previously installed Win7 in IDE mode and failed to switch to AHCI mode, OR, have repeatedly re-install your Windows OS even in AHCI mode.

Problem:
1. You find that your motherboard cannot auto-detect the Intel SSD when POST if SATA is set to AHCI mode. You cannot POST and there is no way to enter BIOS setup until you plug out the SATA cable to SSD. No matter how you set in your BIOS or change SATA cables or SATA port on motherboard, the problem will NOT go away. It may appear that the motherboard has some compatibility issues with Intel SSD on AHCI mode, or you may think the SSD is faulty with AHCI.

Root Cause:
Well, none of hardware is giving problem. The root cause of the issue is the Windows 7 has somehow created a 0KB unused partition every time you do a fresh reformat. I personally see 2 0KB unused partitions when i boot with my Win7 DVD.

Solution (Step by Step) - Revised 31 May 10:
- Your main objective is to get rid of those 0KB Unallocated partition in your SSD. These cause the hanging in the auto-detection of SSD in AHCI mode.

==========================================================
Method to change IDE mode to AHCI Mode under such scenario
==========================================================
1. If your PC still 'hang' on BIOS POST while trying to detect the SSD in AHCI mode, go to your BIOS Setup to change back the SATA mode to IDE. If you cannot even go into BIOS Setup at all, off your power, unplug the SATA cable from SSD, power on PC and you should be able to go into BIOS setup mode now.

2. If you have Acronis True Image or Norton Ghost or equivalent disk imaging software, do a FULL Hard Disk Clone on all your partitions, including the SYSTEM PARTITION on the SSD. The key word is FULL Backup.

3. Boot with your Windows 7 DVD, choose Install. When you are at the Disk Partition page, DELETE ALL PARTITIONS on the SSD. Yes delete ALL. (Assume you have backup data on step1) You will see 150GB Unallocated Space (assuming yours is 160GB). Leave it and Exit the Installation. DO NOT continue.

4. Reboot and Set your SATA to AHCI mode in BIOS. At this point, you will find that your BIOS is able to detect the SSD in AHCI mode!!!!!

5. Boot with your Windows 7 DVD again, choose Install. Now you can create your partitions all over again. You should see a 100MB SYSTEM PARTITION and your remaining set partitions. The 0KB Unused Partitions are completely removed. You can format your own partitions if you wanted to. At this point, you can choose to reinstall your OS (long method) or continue my steps below.

6. Reboot with your Acronis True Image Boot Disk. Do a COMPLETE RESTORATION on all your partitions including the System Partition from your backup image. You must set System Partition as Primary, Active. The rest of partitions including your OS partitions are Primary. You may need to extend those unwanted free space and leaving none.

7. Reboot and go into your BIOS setup. Change the SATA back to IDE mode again. If you forget to go this step and directly boot into windows, you will crash the windows.

8. Assuming your OS restoration is ok, you should see all your stuffs before the start of this exercise.

9. Follow this Microsoft KB http://support.microsoft.com/kb/922976. Do a regedit and change the msahci setting. If you are using Vista/Win 7, changes to AHCI is on the fly. Save the registry.

10. Reboot and go into your BIOS setup. Change the SATA to AHCI mode.

11. Boot into Windows. You will see new drivers being installed and your disk is on AHCI.


=============================================
Simple Steps to change IDE mode to AHCI mode (only if you do not encounter hanging on auto-detection of AHCI during POST)
=============================================
1. Follow this Microsoft KB http://support.microsoft.com/kb/922976. Do a regedit and change the msahci setting. If you are using Vista/Win 7, changes to AHCI is on the fly. Save the registry.

2. Reboot and go into your BIOS setup. Change the SATA to AHCI mode.

3. Boot into Windows. You will see new drivers being installed and your disk is on AHCI.



Evidence:
Check Device Drivers


Check Safely Remove USB icon. You will see now your hard disks are on the list.


Summary:
If you follow this method, you save all the hours reinstalling all your PC. There is NO NEED to RMA your motherboard or Intel SSD as they are perfectly ok.


========================================
If you already have your SSD set to AHCI mode and successfully installed Window 7 before, but if the same problem arises after you do multiple installation, steps are similar, but you need to restore from a last known full backup or maybe you are in midst of a new Windows reinstallation:
========================================

New Clean Installation Method:
1. Boot with your Windows 7 DVD, choose Install. When you are at the Disk Partition page, DELETE ALL PARTITIONS on the SSD. Yes delete ALL. (Assume you have backup data on step1) You will see 150GB Unallocated Space (assuming yours is 160GB). Leave it and Exit the Installation. DO NOT continue.

2. Reboot. At this point, you will find that your BIOS is able to detect the SSD in AHCI mode again!!!!!

3. Boot with your Windows 7 DVD again, choose Install. Now you can create your partitions all over again. You should see a 100MB SYSTEM PARTITION and your remaining set partitions. The 0KB Unused Partitions are completely removed. You can format your own partitions if you wanted to. At this point, you can choose to reinstall your OS (long method) and all your programs again.

4. Do your data restoration to other partition(s) if needed.


Restoration Method:
Warning: Make sure you have a FULL Backup of your data available before proceeding.

1. Boot with your Windows 7 DVD, choose Install. When you are at the Disk Partition page, DELETE ALL PARTITIONS on the SSD. Yes delete ALL. (Assume you have backup data on step1) You will see 150GB Unallocated Space (assuming yours is 160GB). Leave it and Exit the Installation. DO NOT continue.

2. Reboot. At this point, you will find that your BIOS is able to detect the SSD in AHCI mode again!!!!!

3. Boot with your Windows 7 DVD again, choose Install. Now you can create your partitions all over again. You should see a 100MB SYSTEM PARTITION and your remaining set partitions. The 0KB Unused Partitions are completely removed. You can format your own partitions if you wanted to.

4. Reboot with your Acronis True Image Boot Disk. Do a COMPLETE RESTORATION on all your partitions including the System Partition from your backup image. You must set System Partition as Primary, Active. The rest of partitions including your OS partitions are Primary. You may need to extend those unwanted free space and leaving none.

5. Assuming your OS restoration is ok, you should see all your stuffs before the start of this exercise.

[soulblader_86]

I shld download AHCI driver from gigabyte or Intel website?

which is better?

[junkirio]

finally found this thread, after searching for so long for unallocated space 0 mb problem. btw hdd also got this problem, not only ssd.

[ry0suk1]

TS maybe you can include the why how to Raid + Trim for intel X25-M so it will be all in one guide..

[wmsoon]

I am unable to find where to enable AHCI mode in my Bios. My MB is a MSI P965 Neo. After I unstalled Wind 7, I checked the hardware device manager as shown in your webshot & its shows: Intel (R) ICH8 2 port Serial ATA Storage Controller. Does this mean my MB does not have/support Standard AHCI Serial ATA Controller?

[yangzhaoyu20]

hope this will work for me

[final1]

I have an Intel x25m G1 ssd with this exact same problem! I thought it was spoilt but now you give me hope to fix it... Will try it out.

[Lola Honner]

Thank you for your great posts.

[Mankul]

My desktop somehow crashed and when I restarted, it cannot detect the boot disk.

-Bios is able to detect the ssd but when I use the windows 7 64bit DVD in recovery mode, it cannot detect the ssd.

-I took out the ssd and load it externally to another laptop, it was able to detect the ssd in windows 7 but has only one partition of 0KB.

So I think the partition table is screwed up already.

Question: Is my data still recoverable in the sdd?

The challenge:
In the guide here, he suggested to back up and then do a proper format of the ssd. The thing is, I do not want to lose my current data. Is it possible to restore the partition table and get it working as per normal? There is already a previously installed windows7 in the ssd.

Thank you so much in advance for your inputs. My head is spinning now. Need my desktop to be working again.

[jtjt00]

Mankul wrote:

My desktop somehow crashed and when I restarted, it cannot detect the boot disk.

-Bios is able to detect the ssd but when I use the windows 7 64bit DVD in recovery mode, it cannot detect the ssd.

-I took out the ssd and load it externally to another laptop, it was able to detect the ssd in windows 7 but has only one partition of 0KB.

So I think the partition table is screwed up already.

Question: Is my data still recoverable in the sdd?

The challenge:
In the guide here, he suggested to back up and then do a proper format of the ssd. The thing is, I do not want to lose my current data. Is it possible to restore the partition table and get it working as per normal? There is already a previously installed windows7 in the ssd.

Thank you so much in advance for your inputs. My head is spinning now. Need my desktop to be working again.

I suggest you get a new SSD to install your OS and a USB3.0 casing to insert your old SSD for recovery later.