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I have installed Windows 7 on my PC (Gigabyte ga-p55-ud5) with the SATA controller set on RAID mode. After that, I've decided to try to install Mac OS X and to do so I had to set my SATA controller to AHCI.

Windows 7 only starts if I set it to RAID, Mac OS X only if I set it to AHCI.

Is there any way to let Windows 7 boot in AHCI mode without installing it from scratch?

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up vote 3 down vote accepted

Windows 7 doesn't have AHCI drivers loaded by default. Boot with raid, then enable the AHCI drivers then restart and enable AHCI in the bios. This KB explains how to., but is not a complete guide.

See this page for additional suggestions if the MS article does not work for your situation.

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The problem is that you installed Windows 7 while in raid mode. If you had installed it while the motherboard was in AHCI mode.

I do not have links, but in my experience, when changing the mode in bios it prompts you about that issue and I have had booting issues when it wasn't set to the mode the OS was installed in.

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