The Sigverif.exe Tool Signature Verification
Article by Marc Liron - Microsoft MVP (2004-2010)
Many issues that you may experience on a Windows XP based computer occur because of an incompatible or corrupted program or hardware. When narrowing down the issue further it is often found to be what is called a driver problem.
To determine whether this is the case, you can either perform a series of steps to isolate the driver in question.
What Is A Driver?
A program that controls a device. Every device, whether it be a printer, disk drive, or keyboard, must have a driver program. Many drivers, such as the keyboard driver, come with the operating system. For other devices, such as an iPod, you may need to load a new driver when you connect the device to your computer. In Windows XP drivers often have a .DRV extension.
The SIGVERIF.EXE Tool...
Microsoft has a program in place to ensure that device drivers are reliable and unlikely to cause problems on your computer. When Microsoft developers and 3rd party vendors create a new driver it can be submitted to a special department within Microsoft for "device signing".
...sadly not all 3rd party vendors do this and this can result in device-driver problems. For instance a might be a driver was not correctly written for Windows XP.
Fortunately Microsoft has added a tool within Windows XP to determine what signed and unsigned drivers exist on your system. It is called the "Signature verification Tool"
To use the tool follow these instructions:
1. Click Start, click Run, type sigverif, and then click OK.
2. Click Advanced, click Look for other files that are not digitally signed, navigate to the C:\WINDOWS\SYSTEM32\DRIVERS folder, and then click OK.
3. Click Start.
After Sigverif.exe is finished running its check, a list of all unsigned drivers installed on your computer are displayed.
The list of all signed and unsigned drivers found by Sigverif.exe can be found in the Sigverif.txt file in the Windows folder on your computer. All unsigned drivers are noted as Unsigned.
How To Remove Unsigned Drivers:
Please Note many video drivers are not digitally signed. The following steps may cause problems with your video resolution. These problems may prevent you from starting the computer....
When you determine which drivers are unsigned, create a folder to move the unsigned drivers to. Typically, SysDriversBak is an easy folder name to remember.
Move the unsigned drivers, restart the computer (without the unsigned drivers in the Windows\System32\Drivers folder), and then test the program or other functionality to see whether the same error messages or issues still occur.
Note Because most driver files are associated with registry entries that have not yet been changed, you may receive the following error message:
At least one driver or service failed to start...
If the issue no longer occurs, the issue was caused by a third-party unsigned filter or function driver.
A function driver is a driver that is used to load a specific device that uses one of the computer buses. A filter driver loads at a level above or below a function driver to add or modify the behavior of the function driver.
To determine which unsigned driver is causing the problem, use one of the following methods:
# Put drivers that are related to the same program or device back into the Windows\System32\Drivers folder together in the same test.
# Put the top half of the drivers back into the Windows\System32\Drivers folder in the same test.
The first technique is generally better at determining the cause of an issue, but you may not be able to determine which drivers are related. After you determine which driver is causing the issue, you can either remove the driver or program, disable the driver, or turn off service.
If you need to turn off a service, follow these steps:
1. Click Start, and then click Run.
2. Type %systemroot%\system32\services.msc /s, and then click OK.
3. Double-click the service, click Disabled in the Startup Type list, and then click OK.
4. Restart your computer.
If you need to disable a driver, follow these steps:
1. Click Start, and then click Run.
2. Type %systemroot%\system32\compmgmt.msc /s, and then click OK.
3. Click Device Manager.
4. Double-click the device, click Do not use this device (disable) in the Device Usage list, and then click OK.
5. Search for an updated driver for the device from the vendor.
The process of discovering a "faulty" driver can take a while!
Once you have isolated the driver search for drivers or other program updates, or replace the software or driver with a program or driver that is written specifically for Windows XP.
For information about how to contact the manufacturer of your program, click the appropriate article number in the following list to view the article in the Microsoft Knowledge Base:
65416 ( http://support.microsoft.com/kb/65416/ ) Hardware and Software Third-Party Vendor Contact List, A-K
60781 ( http://support.microsoft.com/kb/60781/ ) Hardware and Software Third-Party Vendor Contact List, L-P
60782 ( http://support.microsoft.com/kb/60782/ ) Hardware and Software Third-Party Vendor Contact List, Q-Z
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