Cannot start Win7 in AHCI mode when multiple drives are connected

One possible problem may be that you first set your boot drive order and then set the mode to ACHI.

I had a similar problem on my gigabyte motherboard a couple of days ago when I copied my old boot drive to a new SSD.

In essence, the problem occurs because when you change the access type from IDE to ACHI, a different internal controller is used which in effect changes your booot order because the ACHI mode is now considered as a SCSI type of device which is commmon when one isn't using the IDE mode.

If you check your boot sequence, youmay find that it is now pointing to a different location than what you want.

Once I reset by boot order AFTER setting the BIOS to ACHI, the motherboard instantly found the correct boot drive.

I would hazard that your SSD has an internal disk id other than C: and your old drive still has the C:.

One other thought regarding alignment, While I was still running WIN 7 PRO using a regular hard drive, I simply used the Disk management function under 'my computer\manage\disk manager' to initialize my new SSD and create the new boot partition. Under WIN 7 this does assign the correct alignment.

I then used my backup CD copy of Acronis True Image Home 2011 (ATIH2011)to simply copy my previously backuped WIN 7 OS partition to the newly created partition on the SSD. I did the restore of the OS partition only, not copying the boot part with sector 1. After I copied the OS partition, I then copied the boot part in a seperate step which only takes a couple of seconds.

Note: When ATIH2011 makes a backup copy of a PARTITION, it creates both a copy of the partition and another smaller copy of the boot sector. When doing a 'restore' of a boot partition, do not use the 'CLONE' function, use the partition restore function instead. If your current hard drive (HDD) has multiple partitions on it that you want to copy to a SSD, first 'restore' the partition containing the OS, then the 'boot partition' and then whatever other partitions that you want.

I spent a few days researching how to copy from a HDD to a SSD while maintaining the correct alignment and basically, the way that I did it does work correctly.

Any hard drives other than the boot drive are not affected by changing from IDE to ACHI mode other than working faster.

Finallymotherboards differ in how the use the BIOS and therefore the above procedure might not work correctly. During my ersearch, I did find several other users who did the migration from IDE HDD to a ACHI SSD using the above procedure with no problems at all other than what you have experienced with the boot failure due to the actual controller being invoked which then changes the actual internal address of the new SSD boot drive.

Interesting scores, thanks. So AHCI actually gave a very significant speed boost, mostly for reading.

I ended up biting the bullet and reinstalled Windows in AHCI with my HDDs all connected in the manner which I'd like to use them after installation. Now everything is working correctly, and it's very satisfying :P

I guess the problem might have been something to do with having changed which port my SSD drive was connected to, but I'm pretty sure I changed it back afterwards. Also, interestingly, while my SSD Win7 install initially booted in AHCI mode when only it was connected, after messing about with everything it would no longer boot into Win7 in AHCI even if it were the only device connected. Also, what helped encourage me to just reinstall Windows is that problems became progressively worse, with blue screens and then I couldn't even boot into Windows at all anymore, it would stay on the "Preparing your desktop" screen, and this was after getting a bluescreen while transferring files from one HDD to another. So maybe playing with the ports after installation totally screwed things up (though multiple connected HDDs prevented Win7 booting even right after the initial install), or maybe there was an issue with there being Win7 installed on 2 of the HDDs (though on the old one the directory had been renamed).

Just one of the quirks with setting up a new PC, I guess. Since my reinstall, I haven't had a single problem, everything is running great, and in AHCI mode.

Thanks for the help Dustsailor and DGLang!

I suspect that in your case, you checked to be sure that your BIOS was pointing to the correct drive.

One thing that I have experienced when installing WIN 7 is that if one has a >2.2TB Advanced Format (AF) HDD installed, WIN 7 insists on installing on one of the AF HDDs even though you may have specified another drive and windows doesn't warn you that it actually installed on another drive.

If you do have an AF HDD on your computer and you want to verify that Windows actually wound up where you wanted it, you can check by powering off and unplugging all but your desired boot drive and then booting up again. Obviously if you can boot up you are OK, but if you can't boot up, at least part of your boot partition is on another drive which is now disconnected.

In my case, since I had three AF HDDs installed along with 2 500 gb drives and my SSD, I wound up with bad installs on all of my AF drives as well as the SSD.

I recently spent over a full week trying to find out why WINDOWS wasn't installing on the drive I told it to. The simple soultion was to unplug all of the other drives leaving only the desifred drive available to install on. The reason for the install was that I had just upgraded my motherboard and processor and I needed to install the correct motherboard chipset drivers. I have a very large installation with dozens of programs and it is a major pain and very time consuming to do a complete install from scratch along with reinstalling all of my programs due to licensing restrictions. I usually just do a sysprep and then install all of the correct drivers, but this time, Windows wasn't cooperating at all.

Even trying to do a 'windows repair' fails with windows trying to put the 'repaired' partition on one of the advanced format drives. Once again, this after one specifies which drive to install on. Windows still doesn't advise which HDD it actually 'repaired'.

One of the reasons it took so long was when I finally got a 'basic' win 7 HP partition installed, I had to reinstall Acronis True Image on that partition to get access to my backups in the 'Acronis Secure Zone'. Once one reinstalls Acronis and directs it to use the 'Secure Zone', Acronis doesn't check to see there is already one existing, but instead creates a new empty 'Secure Zone. with all of the previous backups gone.

A second problem with Acronis that I've experienced is that if you place the backups in a partition that gets defragged and the backup image gets defragged, it lo longer passes 'validation' and is unusable.

The solution to those two problems is to place one's backups in a smaller dedicated partition which never gets defragged and Acronis doesn't create or delete.