Windows 10 Upgrader error: api-ms-win-core-libraryloader-l1-1-1.dll is missing from your computer

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Microsoft’s Windows 10 Upgrade Assistant is an easy GUI based tool for upgrading Windows 7, 8, 8.1 to Windows 10.Other than that, you can also use this to get a Windows 10 ISO for offline upgrade.

It is a nifty tool but like any other softwares, you can at certain instances encounter an error message that says “api-ms-win-core-libraryloader-l1-1-1.dll is missing from your computer.

This driver file is not a native file of Windows. Users began experiencing this after the release of Windows 10 Fall Creators Update.

Thus the release of an update called Windows 10 Upgrade Assistant to address issues on newer versions of Windows. For those who on an older version and want to upgrade to Windows 10 very smoothly, here is an easy way to fix it.

  • Open File Explorer and navigate to C:\Windows\System32\
  • Once there, search for wimgapi.dll
  • Once you find it, Copy the file to C:\Windows10Update\

October 2021 Update:

You can now prevent PC problems by using this tool, such as protecting you against file loss and malware. Additionally it is a great way to optimize your computer for maximum performance. The program fixes common errors that might occur on Windows systems with ease - no need for hours of troubleshooting when you have the perfect solution at your fingertips:

  • Step 1 : Download PC Repair & Optimizer Tool (Windows 10, 8, 7, XP, Vista – Microsoft Gold Certified).
  • Step 2 : Click “Start Scan” to find Windows registry issues that could be causing PC problems.
  • Step 3 : Click “Repair All” to fix all issues.


  • You will be prompted to Replace to existing file. Confirm this and accept any message that requires admin permission.
  • Restart the upgrade process and Enjoy Windows 10!

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