Error code when you try to use Windows Update or Microsoft Update to install updates: "0x800B0001"


When you try to install updates from the Windows Update or Microsoft Update Web site, you receive the following error code:


This issue occurs if Windows Update or Microsoft Update determines that the cryptographic service provider is unknown.


To resolve this issue, follow the steps that are appropriate for your particular operating system.

To have us register the dll files for you, go to the "Fix it for me" section. If you prefer to fix this problem yourself, go to the "Let me fix it myself" section.

Fix it for me

To fix this problem automatically, click the Fix it button or link. In the File Download dialog box, click Run,and then follow the steps in the Fix it Wizard.

  • For Windows Vista and Windows Server 2008, the Fix it solution only perform Method 2 for you, so you still need to perform Method 1 manually.
  • This wizard may be in English only. However, the automatic fix also works for other language versions of Windows.
  • If you are not on the computer that has the problem, save the Fix it solution to a flash drive or a CD and then run it on the computer that has the problem.

Then, go to the "Did this fix the problem?" section.

Let me fix it myself

In Windows XP, in Windows Server 2003, and in Windows 2000

To resolve this issue, you must register the Softpub.dll, Wintrust.dll, Initpki.dll, and Mssip32.dl files. To do this, follow these steps:
  1. Start Notepad. To do this, click Start, and then click Run.
  2. Copy and then paste (or type) the following command in the Open box, and then press ENTER:
  3. Copy and then paste (or type) the following command lines into the Notepad window:
    regsvr32 Softpub.dll /s
    regsvr32 Wintrust.dll /s
    regsvr32 Initpki.dll /s
    regsvr32 Mssip32.dll /s
  4. On the File menu, click Save As, and then type Register.bat.
  5. Click Save as type, and then click All Files.
  6. Save the Register.bat file to your desktop.
  7. Double-click the Register.bat file to register the Windows Update files.
  8. Try to install updates again.
  9. If the issue is resolved, delete the Register.bat file that you created in the previous steps.

In Windows Vista and in Windows Server 2008

Method 1: Run the System Update Readiness tool (Checksur.exe)

  1. Download and run the System Update Readiness tool (Checksur.exe). After you download this tool, it runs a one-time scan for inconsistencies that might prevent future servicing operations.

    For more information about how to download and run the System Update Readiness tool, click the following article number to view the article in the Microsoft Knowledge Base:

    947821 Description of the System Update Readiness Tool for Windows Vista and for Windows Server 2008

    • In article 947821, scroll down to the "Microsoft Download Center" section, and then click the associated link to download the System Update Readiness tool for your operating system.
    • After you run this tool, the Checksur.log file will be saved in the following location:
      In a default installation of Windows Vista, this is the C:\Windows\Logs\CBS folder.
  2. After the System Update Readiness tool runs, try to install updates again.
If these steps in do not resolve the issue, go to Method 2.

Method 2: Register the Wintrust.dll

  1. Click Start Start button  , and then type cmd in the Start Search box.
  2. In the results list, right-click cmd, and then click Run as Administrator. User Account Control permission If you are prompted for an administrator password or for confirmation, type the password, or click Continue.
  3. At the command prompt, copy and then paste (or type) the following command.
    regsvr32 Wintrust.dll /s
  4. Close the Command Prompt window.
  5. Try to install updates again.

Did this fix the problem?

  • Check whether the problem is fixed. If the problem is fixed, you are finished with this section. If the problem is not fixed, you can contact support.
  • We would appreciate your feedback. To provide feedback or to report any issues with this solution, please leave a comment on the "Fix it for me" blog or send us an email.

Article ID: 958045 - Last Review: Jun 1, 2011 - Revision: 1