Unable to install windows update

Method 1: Rename the Edb.log file

This issue may occur if the hotfix installer references the Edb.log file, and the file is corrupted. To resolve this issue, rename the Edb.log file. To do this, follow these steps:

1. Start Windows Explorer, and then open the following folder: C:\WINDOWS\system32\CatRoot2\
2. Right-click the Edb.log file, and then click Rename. Rename the file 'Edb.old.'
3. Start Internet Explorer, and then open the Windows Update Web site to continue the updates.
   
   

   If you still cannot install the updates, rename the CatRoot2 folder. To do this, follow these steps:

4. Start Windows Explorer, and then open the following folder:
   C:\WINDOWS\system32\
5. Right-click the CatRoot2 folder, and then click Rename. Rename the CatRoot2 folder 'CatRoot2old'. 
6. Start Internet Explorer, and then open the Windows Update Web site to continue the updates.

Method 2: Register the DLL files

This issue may occur if the correct DLL files have not been registered. To register the DLL files, follow these steps:

1. Click Start, click Run, type regsvr32 licdll.dll in the Open box, and then click OK. When you receive the message that the DllRegisterServer succeeded, click OK.
2. Click Start, click Run, type regsvr32 regwizc.dll in the Open box, and then click OK. When you receive the message that the DllRegisterServer succeeded, click OK.
3. If you still cannot install the updates, use the following method:

Method 3: Repair the certificate

This issue may occur if the 'Microsoft Root Authority' certificate or the 'NO LIABILITY ACCEPTED, (c)97 VeriSign, Inc.' certificate under Trusted Root Certification Authorities has been removed. To resolve this issue, follow these steps:

1. On another computer where the Microsoft Root Authority certificate has been installed, open Internet Explorer. 
2. Click Tools, and then click Internet Options. 
3. Click the Content tab, and then click Certificates.
4. Click the Trusted Root Certification Authorities tab.
5. Scroll down, and then click Microsoft Root Authority. 
6. Click Export. 
7. Follow the steps in the wizard to export the certificate to a DER Encoded Binary x.509-format file (.cer file) file on a floppy disk or to a shared folder that is accessible to the computer that cannot install updates. 
8. On the computer that cannot install updates, open Internet Explorer. 
9. Click Tools, and then click Internet Options. 
10. Click the Content tab, and then click Certificates. 
11. Click the Trusted Root Certification Authorities tab. 
12. Click Import. 
13. In the wizard, click Next. 
14. Click Browse to locate the file that you saved to a floppy disk or to a shared folder, and then click Open. 
15. Click Next, click Automatically select the certificate store based on the type of certificate, click Next, and then click Finish.

Method 4: Delete the WUTemp files

This issue may occur if the contents of the WUTemp folder are corrupted. To resolve this issue, delete the Windows Installer temporary files.

Note These files are stored in a hidden folder. You must make the folder visible.

To delete the Windows Installer temporary files, follow these steps:

1. Click Start, and then click My Computer. 
2. On the Tools menu, click Folder Options. 
3. Click the View tab. 
4. Click to clear the Hide protected operating system files (Recommended) check box. 
5. Click the Show Hidden files and folders option, and then click OK. 
6. Double-click Local Disk (C:). 
   
   Note If you have more than one hard disk drive on your computer, the WUTemp folder may be located on another partition. For example, the folder may be D:\WUTemp, or E:\WUTemp.
   
7. Double-click WUTemp.
8. On the Edit menu, click Select All to select all the files in the WUTemp folder.
9. On the File menu, click Delete. If you are prompted to confirm the file deletion, click Yes.
   
   Method 5: Check the firewall, antivirus, and other software

A software firewall is a security system that acts as a protective boundary between a network and the outside world. If you have a firewall installed, it can prevent your computer from connecting to the Windows Update server. Look in the notification area of your desktop (in the lower right corner of your screen) to see if a firewall is running on your computer. In Windows XP, you may have to show all icons in the notification area to reveal your firewall icon. To identify the program that an icon represents, position your pointer over the icon and wait several seconds. When you find the icon for your firewall, right-click the icon. This action may reveal a menu that allows you to temporarily disable the firewall. Some common software firewalls include: ZoneAlarm, Norton Internet Security, McAfee Security, and BlackICE.

To determine if the firewall is causing the issue, temporarily disable the firewall, and then see if the error persists. If disabling the firewall resolves the issue, contact the firewall software manufacturer for directions about how to configure your firewall to allow you to use Windows Update. Make sure that TCP/IP ports 80 and 443 are open in both directions. Make sure that your firewall is not blocking scripting functions on Web sites.

To determine if your antivirus or other software is causing the issue, temporarily disable all non-Microsoft software, such as your antivirus software, or any Web accelerator or Web enhancement programs, before accessing the Windows Update Web site. If disabling the non-Microsoft software resolves the issue, contact the software manufacturer for directions about how to configure your software to allow you to use Windows Update