You may experience Windows Update Error 0x800700c1 when you try to install 2017-05 Cumulative Update for Windows 10 Version 1703 for x64-based system (KB4020102). Because of this error, you may face so many trouble in your PC like hanging windows start button, program not responding, application launches and closes too much slow etc. Apart from this, there may also be security related issues in Windows operating system.

Method 1: Fix using Advanced System Repair Tool

The most of the common reason behind windows update failed is corrupted or damaged system files like DLL files, EXE files, sys files etc. There are thousands of tiny system files are there that work specific task. If one of the files gets replaced, deleted or damaged then you may get windows update error 0x800700c1.

Download and Install Advanced System Repair Tool and scan your PC. It has the large database with 25 million of files. It will find all the damaged or deleted system files and reinstall them with the fresh one. After, optimizing with Advanced System Repair Tool, try to install windows update again.

Method 2: Reset Software Distribution Folder.

Software Distribution Folder contains all the installed updates files. If this folder has corrupted installation file then it may prevent your pc from installing latest updates. Resetting Software Distribution Folder is a very good idea to figure out this problem. Here are complete steps to Reset Software Distribution Folder.

Step 1: Open Command Prompt as Administrator

Step 2: Now run following command one by one.

net stop wuauserv
net stop bits
net stop cryptsvc

ren %systemroot%\System32\Catroot2 Catroot2.old
ren %systemroot%\SoftwareDistribution SoftwareDistribution.old

net start wuauserv
net start bits
net start cryptsvc

Step 3: Close Command Prompt and try to update again.

Method 3: Run DISM Command to Fix this Error

DISM command is a short form of Deployment Image Servicing and Management (DISM.exe). This command generally repairs updates problems and allows your PC to install latest updates without any error. Here, is the complete guide on How to use DISM Command in Windows 10.

Step 1: Open Command Prompt as Administrator.

Step 2: Run following commands one by one. It may some time to finish so be relaxed and keep patience.

DISM /Online /Cleanup-Image /ScanHealth
DISM /Online /Cleanup-Image /CheckHealth
DISM /Online /Cleanup-Image /RestoreHealth

Step 3: After finishing this process, try to install windows update again.

Method 4: Disable Antivirus, Windows Defender, and Firewall for a while

Antivirus and Firewall may cause the 0x800700c1 problem also. The firewall may block the incoming connection for updates if it finds some suspicious file in it. It may also block the installation of updates if it finds the suspicious file in it. Disable antivirus and firewall for short moment and then try to install updates. Most probably you will not get the above error.

Method 5: Run System Update Readiness Tool

System Update Readiness Tool is a small tool that is developed and distributed by Microsoft itself. This tool is used for repairing Update related problems in Windows 7. You can download this tool from the following link:

https://microsoft.com/en-in/download/details.aspx?id=20858

After installing this tool, run it as administrator. It will automatically reset all the components of windows update and provide you clean environment for installing windows updates.

Summary

This article discussed 5 methods to fix Windows Update Error 0x800700c1. If you are also facing the same error and unable to find a solution to fix it, then this article might help you a lot.