Upgrading Vista to Windows 7 fails with error 0xc0000359 and reference to iastor.sys

When trying to upgrade from Vista to Windows 7, upgrade process fails with error message and rolls back to Vista.

\$windows.~bt\windows\system32\drivers\iastor.sys

Status: 0xc0000359
Windows failed to load because a critical system driver is missing or corrupt

During upgrade process the incorrect version of the iastor is referenced resulting in the above error.

To resolve this issue perform the following steps:

1. Access Driver Repository Folder under C:\Windows\System32\DriverStore\FileRepository and move any folders that contain the file: iastor.inf to a temporary location.

Note: To move the files from the FileRepostiry you may require additional permissions which can be accomplished by taking ownership of the the folder:

• Right-click on the folder and choose Properties,
• Click Security tab.
• Click Advanced button.
• Click Owner tab.
• Click Edit button.
• Select your account.

2. Search for references to iastor within the oem inf files in the c:\windows\inf folder.

Example Command: findstr /i /c:"iastor" %windir%/inf/oem*.inf

3. Make a note of the oem##.inf files reported where ## is a numeral.  Move the oem##.inf and corresponding oem##.pnf from c:\windows\inf folder to a temporary folder.

4. Delete $~bt, $~LS and $~Upgrade folders from c:\ drive if they exist

5. Download and install the latest version of the iastor.sys driver from Intel website on the Vista machine: http://downloadcenter.intel.com/Detail_Desc.aspx?agr=Y&DwnldID=17882&lang=eng

6. Start the Windows 7 upgrade process. It should complete successfully now.

Note: Once the Upgrade process has completed successfully, there is no need to restore the iastore files, or the oem*.inf and oem*.pnf files back to their original location as the devices will no longer be needed.

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