How to Use the File Signature Verification
File Signature Verification (Sigverif.exe) detects signed files and allows you to:
Unsigned or altered drivers cannot be installed on x64-based versions of Windows.
signing is a multistage process in which device drivers are verified.
For a driver to earn this certification, it must pass a series of
compatibility tests administered by the Windows Hardware Quality Labs
(WHQL). Because of stringent WHQL standards, using signed drivers
typically results in a more stable system. When troubleshooting a
problem that might be caused by a driver, you might choose to remove
unsigned drivers to eliminate the possibility that the unsigned driver
is causing the problem. While most unsigned drivers will not cause
problems, they have not been verified by Microsoft and therefore have a
higher risk of causing problems than signed drivers. Microsoft
digitally signs drivers that pass the WHQL tests, and Windows Vista
performs signature detection for device categories such as:
Microsoft Corporation digital signature indicates that a driver file is
an original, unaltered system file that Microsoft has approved for use
with Windows Vista. Windows Vista can warn or prevent users from
installing unsigned drivers. If a driver is not digitally signed, the
user receives a message that requests confirmation to continue.
Microsoft digitally signs all drivers included with the Windows Vista
operating system CDs. When you download updated drivers from a
manufacturer’s webpage, always select drivers that are signed by
The following tools are useful for troubleshooting problems caused by unsigned files:
To identify unsigned drivers, follow these steps:
Click Start, and then type Sigverif. Press Enter.
In the File Signature Verification window, click Start.
After several minutes, the Signature Verification Results page displays
unsigned drivers. Unsigned drivers can be reliable, but they have not
undergone the same testing required of signed drivers. If you are
experiencing reliability problems, you should replace unsigned drivers
with signed versions from Microsoft or the manufacturer.
Click Close to return to the File Signature Verification window.
Click Close again.
How to Use Device Manager to View and Change Resource Usage
new hardware or updating drivers can create conflicts, causing devices
to become inaccessible. You can use Device Manager to review resources
used by these devices to manually identify conflicts. Typically,
however, you should let Windows Vista automatically allocate resources.
With modern hardware, there is almost never a valid reason to manually
adjust resource usage, and you might cause more problems than you
To use Device Manager (Devmgmt.msc) to view or change system resource usage information, follow these steps:
Click Start, right-click Computer, and then click Manage.
Click Device Manager, and then double-click a device.
Click the Resources tab to view the resources used by that device.
Click a resource, and then clear the Use Automatic Settings check box.
Click Change Setting, and then specify the resources assigned to the device.