Windows 7 / Getting Started

How to Use the File Signature Verification

File Signature Verification (Sigverif.exe) detects signed files and allows you to

  • View the certificates of signed files to verify that the file has not been tampered with after being certified.
  • Search for signed files.
  • Search for unsigned files.

Note Unsigned or altered drivers cannot be installed on x64-based versions of Windows.

Driver 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. Although 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 performs signature detection for device categories such as:

  • Keyboards
  • Hard disk controllers
  • Modems
  • Mouse devices
  • Multimedia devices
  • Network adapters
  • Printers
  • SCSI adapters
  • Smart card readers
  • Video adapters

A Microsoft Corporation digital signature indicates that a driver file is an original, unaltered system file that Microsoft has approved for use with Windows. Windows 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 Windows or distributed by Windows Update. When you download updated drivers from a manufacturer's Web page, always select drivers that are signed by Microsoft.

The following tools are useful for troubleshooting problems caused by unsigned files:

  • File Signature Verification
  • Device Manager
  • Driver Verifier Manager

To identify unsigned drivers, follow these steps:

  1. Click Start and then type Sigverif. Press Enter.
  2. In the File Signature Verification window, click Start.
  3. After several minutes, the Signature Verification Results page displays unsigned drivers. Unsigned drivers can be reliable, but they have not undergone the same testing that is required of signed drivers. If you are experiencing reliability problems, you should replace unsigned drivers with signed versions from Microsoft.
  4. Click Close to return to the File Signature Verification window.
  5. Click Close again.
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In this tutorial:

  1. Troubleshooting Hardware, Driver, and Disk Issues
  2. Windows 7 Improvements for Hardware and Driver Troubleshooting
  3. Windows Troubleshooting Platform
  4. Built-in Troubleshooting Packs
  5. Windows Troubleshooting Platform Components
  6. Creating Custom Troubleshooting Packs
  7. Running Troubleshooting Packs Remotely
  8. Windows 7 Reliability Monitor
  9. Windows 7 Resource Monitor
  10. Windows Memory Diagnostics
  11. Disk Failure Diagnostics
  12. Self-Healing NTFS
  13. Improved Driver Reliability
  14. Improved Error Reporting
  15. The Process of Troubleshooting Hardware Issues
  16. How to Troubleshoot Problems That Prevent Windows from Starting
  17. How to Troubleshoot Problems Installing New Hardware
  18. How to Troubleshoot Problems with Existing Hardware
  19. How to Troubleshoot Unpredictable Symptoms
  20. How to Diagnose Hardware Problems
  21. How to Use Device Manager to Identify Failed Devices
  22. How to Check the Physical Setup of Your Computer
  23. How to Check the Configuration of Your Hardware
  24. How to Verify That System Firmware and Peripheral Firmware Are Up to Date
  25. How to Test Your Hardware by Running Diagnostic Tools
  26. How to Simplify Your Hardware Configuration
  27. How to Diagnose Disk-Related Problems
  28. How to Use Built-In Diagnostics
  29. How to Use Reliability Monitor
  30. How to Use Event Viewer
  31. How to Use Data Collector Sets
  32. How to Use Windows Memory Diagnostics
  33. Memory Failures
  34. How Windows Automatically Detects Memory Problems
  35. How to Schedule Windows Memory Diagnostics
  36. How to Start Windows Memory Diagnostics When Windows Is Installed
  37. How to Start Windows Memory Diagnostics from the Windows DVD
  38. How to Configure Windows Memory Diagnostics
  39. How to Troubleshoot Disk Problems
  40. How to Prepare for Disk Failures
  41. How to Use ChkDsk
  42. ChkDsk Examples
  43. ChkDsk Syntax
  44. How to Use the Graphical ChkDsk Interface
  45. How to Determine Whether ChkDsk Is Scheduled to Run
  46. ChkDsk Process on NTFS Volumes
  47. How to Use the Disk Cleanup Wizard
  48. How to Disable Nonvolatile Caching
  49. How to Troubleshoot Driver Problems
  50. How to Find Updated Drivers
  51. How to Roll Back Drivers in Windows 7
  52. How to Use Driver Verifier
  53. How to Use the File Signature Verification
  54. How to Use Device Manager to View and Change Resource Usage
  55. How to Use Windows 7 System Restore
  56. How to Troubleshoot USB Problems
  57. How to Solve USB Driver and Hardware Problems
  58. Understanding USB Limitations
  59. How to Identify USB Problems Using Performance Monitor
  60. How to Examine USB Hubs
  61. How to Troubleshoot Bluetooth Problems
  62. Troubleshooting Tools
  63. DiskView
  64. Handle
  65. Process Monitor