Msahci Service Defaults in Windows 7

MS AHCI 1.0 Standard Driver by Microsoft Corporation.

Default Settings

Startup type: Manual
Display name:Msahci
Service name:msahci
Service type:kernel
Error control:critical
Group:SCSI Miniport
Registry key:HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\msahci

Default Behavior

Msahci is a kernel device driver. In Windows 7 it won't be started if the user doesn't start it. If Msahci fails to load, Windows 7 attempts to write the error data into Event Log and restart the computer, using the Last Known Good configuration. If the Last Known Good configuration is not valid, Windows 7 startup ends with a Stop error. If you remove or disable the msahci service, Windows 7 won't start.

Restore Default Startup Configuration of Msahci

1. Run the Command Prompt as an administrator.

2. Copy the command below, paste it into the command window and press ENTER:

sc config msahci start= demand

3. Close the command window and restart the computer.

The msahci service is using the msahci.sys file that is located in the C:\Windows\system32\DRIVERS directory. If the file is removed or corrupted, read this article to restore its original version from Windows 7 installation media.