LKBEN10645: STOP 0x0000007B INACCESSABLE_BOOT_DEVICE after changing SATA to AHCI Mode

Symptom

After enabling AHCI Mode in BIOS, Windows Vista will not start with Stop error 7B

Cause

By default, unused drivers will be disabled in Vista. Enabling AHCI Mode in BIOS demands new driver (msahci.sys)

Solution

STOP 0x0000007B INACCESSABLE_BOOT_DEVICE after changing SATA mode of boot drive in Windows Vista or XP

Advanced Host Controller Interface (AHCI) is a special hardware mechanism for use in Serial ATA (SATA) Harddisk controllers which offers features like higher speeds, hot-pluging and native command queuing (NCQ), sometimes in conjunction with RAID support.

However, enbling AHCI in system BIOS might cause your Operating System (OS) like Windows XP or Vista not to load upon startup, causing a Blue Screen with Stop error "0x0000007B INACCESSABLE_BOOT_DEVICE".

Make sure to install the appropriate motherboard or host-adapter drivers prior to switching the mode in your BIOS.

Additionally, in Windows Vista, you might need to enable the AHCI driver (MSAHCI.SYS) by editing the following key:

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Msahci
set "start" to a value of "0".

About the Author

Wim Peeters is electronics engineer with an additional master in IT and over 30 years of experience including time spent in support, development, consulting, training and database administration. Wim has worked with SQL Server since version 6.5. He has developed in C/C++, Java and C# on Windows and Linux in different European countries and different European languages. He writes knowledge base articles to solve IT problems and publishes them on the Lubby Knowledge Platform where he is one of the most important contributors and the main developer.

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