How to Fix Error Code 800b0100

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If you have recently formatted your hard drive and installed a fresh copy of either Windows 7 or Windows Visa, it’s not uncommon for you to encounter the error code 800b0100, while attempting to update the operating system for the very first time.

The error code 800b0100 refers to a problem with Windows update. This error message appears solely when individuals attempt to update their operating system using the Windows update feature. The error message that is typically displayed looks something like the following:

Code 800B0100 Windows Update encountered an unknown error.

This error code is a strong indication of possible data corruption or the deletion of important system files. If you have made several attempts to repair this problem, but to no avail, you needn’t worry, as I will provide you with viable methods of repairing this pesky error.

What Causes Error Code 800b0100

There is definitely more than one reason why the error code 800b0100 may appear on your screen. With that said, following are a number of the more common causes:

  • A corrupted or missing Windows Update component file.
  • Incorrect of corrupt registry keys.
  • A conflict between Windows update and security software (i.e. Firewall).
  • Important .dll files requiring reregistering.

How to Fix It

In order for you to successfully repair this error on your system, you will not need to hire a professional. Despite the prevalence of this error, it is still a fairly easy problem to repair, requiring very little technical expertise. This means you won’t need the skills set of a technician or computer programmer to repair this error.

Below are some of the most common and effective methods deployed by fellow computer users to resolve this error on your system.

Use System Update Readiness Tool

The system update readiness tool is a application created by Microsoft for the sole purpose of repairing Windows updated based errors.

Damaged system files preventing Windows update from determining the version of Windows currently running on your system, is one of many causes preventing Windows update from successfully completing an update.

This is where the readiness tool comes in, as it was designed specifically for repairing such issues. Thus, it’s highly recommended that you use this tool, before you attempt any other method.

Note: When you download and run this tool, it will scan your system, which is a process that may take in excess of 15 minutes. The Windows update process bar may appear to halt at 60%, but that is simply a part of the process. You needn’t worry, nor cancel the repair process.

The system update readiness tool comes in a number of different versions. Simply download the version that is compatible with your operating system, below:

Windows Vista 32-bit:

Windows Vista 64-bit:

Windows 7 32-bit:

Windows 7 64-bit:

Disable Security Software

If the above method failed to fix the problem, then you should consider looking into disabling your security software, as there is a strong chance that it is blocking Windows update from accessing the internet.

Anyway, if you are using the built-in firewall tool, then you can disable it, by doing the following:

1. First, boot into your computer with full administrative rights.

2. Once in, click on Start -> Control Panel.

Start Control Panel

3. When Control panel loads up, click on System and Security.

Click on System and Security

4. From System and Security, click on Windows Firewall.

Start Windows Firewall

5. In the Windows Firewall options, click on Turn Windows Firewall on or off.

Select turn windows firewall on or off

6. In the Customize Settings page, click on Turn off Windows Firewall for Home or work (private) network location settings and Public network location settings and click on OK.

Turn off Windows Firewall for Computer

7. Once you’ve done that, click on OK and try and use Windows update again.

Note: For individuals that are using third party security software, you will need to read the help files of these applications for instructions on how to disable them.

Also, be sure to re-enable it, after you have finished updating Windows, as you’re system will be vulnerable to attack, while it is switched off.

Remove Invalid Registry Keys

If the problem persists, then there is a good chance that the error is due to the registry. In which case, you will need to run a registry cleaner to scan your system and locate these invalid registries keys and remove them.

This is where RegCure Pro comes in, as it is a highly efficient registry cleaner tool, which is capable of scanning your entire system and removing all unnecessary and obsolete files and registry entries. It’s a tool designed to optimise, maintain and secure your system.

You can pick this tool up here:

Run System Restore

Running system restore can be a very smart way of fixing those hard to fix errors. The drawback is that you will need to restore your system back to a point, when it had no errors, so those restore points will already have to be saved on your system.

If you have never used system restore, then there is a good chance that it has not been enabled, in which case, this method will not work, but in the event that you have. Then you should definitely consider using it.

You can run this tool by doing the following:

1. First, boot into your computer with full administrative rights.

2. Then click on Start -> type System Restore (into the Search programs and files box) and press Enter.

Start System Restore

3. Once System Restore, click on Next.

Click Next on System Restore

4. On the following page, select a Restore Point, and then click on Next.

Select Restore Point and click Next

5. Lastly, click on Finish, to restore your system back to a previous state.

Click Finish on System Restore

Re-register Wintrust.dll File

Another method that has proven successful at fixing error code 800b0100 is the re-registering of the Wintrust.dll file. This is a fairly simple process, which can be done, by doing the following:

1. First, boot into your computer with full administrative rights.

2. Then click on Start -> Type cmd (into the Search programs and files box) and Press CTRL + Shift + Enter, and then click on OK.

Start Command Prompt

3. Once Command Prompt loads up, type regsvr32 wintrust.dll and Press Enter.

Put in regsvr32 wintrust.dll and press Enter

4. Then type net stop cryptsvc and Press Enter.

Put in net stop cryptsvc and press Enter

5. Once you’ve type the above command, type ren %systemroot%\system32\catroot2 oldcatroot2 followed by Enter.

type ren %systemroot%\system32\catroot2 oldcatroot2

6. Then type net start cryptsvc and Press Enter.

type net start cryptsvc

7. Once you’ve done all that, run Windows update.

Remove All Windows Update Data

This is probably the most difficult method of all, as it entails disabling certain components and removing data from specific folders. So you should only attempt this method, if you feel comfortable doing these kinds of things. Anyway, the instructions are as follows:

1. First, boot into your computer with full administrative rights.

2. Then click on Start -> Control Panel.

Start -> Control Panel

3. From Control Panel, click on System and Security.

Select System and Security

4. Then click Turn automatic updating on or off, under Windows Update.

Select Turn automatic updating on or off

5. Lastly, select never check for updates, from the drop down menu, and click on OK.

Click on never check for updates

Once you’ve done that, you will need to navigate to the following folders and delete all the contents from them:

  • C:\Windows\SoftwareDistribution\Download
  • C:\Windows\SoftwareDistribution\DataStore
  • C:\Windows\SoftwareDistribution\DataStore\Logs

You can do this, by doing the following:

1. Click on Start, then type C:\Windows\SoftwareDistribution\Download (into the Search programs and files box) and press Enter.

Access C:\Windows\SoftwareDistribution\Download Directory

2. When the folder loads up, click on Organize -> Select All.

Select Organize -> Select All

3. Then click Organize -> Delete.

Select Organize -> Delete

Note: When the warning notification box appears, click on Yes.

Repeat steps 1 – 3 for the remaining two folders, then navigate to the following web page and download the Windows Update reset tool, for your operating system:

This tool is designed to automate the process of fixing error code 800b0100. Simply download the Windows 7/Vista version of the tool, and run it; once it’s finished you will need to restart your system.

Note: The tool provides you with two options, which are Default and Aggressive.

Once you have restarted your computer, be sure to turn Windows update back on by following the steps above. When you get to the Windows update option, select Install updates automatically, then click on OK.

Additionally, if running the Microsoft fix-it tool in Default mode doesn’t successfully fix Windows update, then try running it in Aggressive mode, while following the above instructions.

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  • Anh Nguyễn Ngọc

    Nice, what about some Windows 10 error? Many people upgrade

    • It’ll be a while before Microsoft iron out all of the driver issues, which is part and parcel of a new operating system. So until that time, many people will likely revert back to their previous operating systems (Windows Vista/7/8).

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