“api-ms-win-crt-runtime-l1-1-0.dll is missing” — what it means and the real fix

That intimidating file name is one piece of Microsoft's modern C runtime (the “Universal CRT”). The message means a program needs it and the PC doesn't have a working copy — usually because the Visual C++ 2015–2022 Redistributable was never installed, was damaged, or (on older Windows) a required system update is missing.

The fix, in order

  1. Install the Visual C++ Redistributable from Microsoft. Download “Visual C++ Redistributable for Visual Studio 2015, 2017, 2019 and 2022” from Microsoft's site and run both installers — vc_redist.x64.exe and vc_redist.x86.exe — even on 64-bit Windows. Programs need the flavour they were built with. Restart afterwards.
  2. If it's already installed, repair it. Settings → Apps → “Microsoft Visual C++ 2015–2022 Redistributable” (both entries) → Modify → Repair.
  3. On Windows 7 or 8.1, install the Universal CRT update too (KB2999226, via Windows Update). The redistributable depends on it there; without it, the same error returns after a “successful” install. Windows 10/11 include it already.
  4. Run Windows Update fully and restart — pending updates leave the runtime half-registered surprisingly often.
  5. Reinstall the program that showed the error if it persists — its own installer may have shipped a private, broken copy of the runtime beside the .exe.
Never download api-ms-win-crt-runtime-l1-1-0.dll (or any DLL) from a DLL-download site. That file is one of dozens of interlocking pieces; a lone copy dropped into a folder routinely causes the next error, and those sites are a known malware channel. The complete, signed package from Microsoft is free and takes two minutes.

Why this happens

From 2015 onward, Microsoft moved the C runtime into a shared system component. Programs built with modern tools assume it exists. Fresh Windows installs that skipped optional updates, aggressively “cleaned” PCs, and older Windows 7/8.1 machines are where it goes missing. Nothing about the error implicates the program that displayed it — it's the victim, not the cause.

If it still happens

Check for a stray copy: look in the failing program's own folder for files named api-ms-win-crt-*.dll or ucrtbase.dll. A partial private copy there shadows the good system one — rename that folder's copies (don't delete) and restart the program. If no stray copies exist and repairs hold everywhere else, run sfc /scannow from an administrator Command Prompt to repair the system component store.

Common questions

Is the missing DLL a virus? No — it's a genuine Microsoft system component that is absent or damaged. The virus risk is in the “free DLL download” sites that advertise it.

x64 or x86 — which installer? Both. On 64-bit Windows the two redistributables serve different programs; installing both is the standard, safe move.

Related errors

MSVCP140.dll missing · VCRUNTIME140.dll missing · Visual C++ Runtime Library error