The file api-ms-win-core-windowserrorreporting-l1-1-1.dll is a Windows "ApiSet" stub file used by applications to access Windows Error Reporting (WER) functions. If you are seeing an error related to this file, it usually means a program is trying to run on an older or incompatible version of Windows, or the system's runtime libraries are corrupted. Technical Overview

Location: Usually located in C:\Windows\System32 or C:\Windows\SysWOW64.

If you see an error like: "The program can't start because api-ms-win-core-windowserrorreporting-l1-1-1.dll is missing", the file itself is not broken. The problem is your application is incompatible with your Windows version.

In essence, the "work" of apimswincorewindowserrorreportingl111dll is redirection and contract enforcement.