Windows 7 to Windows 10 Upgrade: Fix The api-ms-win-core-libraryloader-l1-1-1.dll Is Missing Error

Recently I have been upgrading my windows systems to Windows 10 as the deadline for free upgrade was approaching. I first tried to upgrading my HP laptop which has Windows 8 installed, the upgrade went smoothly without a glitch. However when upgrading from Windows 7 I encountered the error:


api-ms-win-core-libraryloader-l1-1-1.dll Is missing

The information is rather vague, it simply refuses to continue the upgrade, but it does not specify where to look for the missing file or what the file is.


So from some research, it appears that it only happens when:

  1. Performing upgrade
  2. Upgrade is done from Windows 7


To fix the issue, we need to carry out the following action. Copy the file:




To the following location and replace the file with the same name in that location:




Apparently Microsoft probably have place/used the wrong file when packaging the release, but luckily we have a solution to work around it. After the file replacement the upgrade went smoothly without any further issues.


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