I ran into an issue trying to upgrade a Windows 7 machine to Windows 10. I kept getting an error that said…
Windows10UpgraderApp.exe - System Error
The program can’t start because api-ms-win-core-libraryloader-l1-1-1.dll is missing from your computer. Try reinstalling the program to fix this problem.
I read through this article and found the solution and I wanted to re-post it for my future use.
Close the Windows 10 updater app, if open.
Copy the file at
Replace the file at
That’s it! You should be able to upgrade to Windows 10 without any other DLL issues.