What is api-ms-win-crt-multibyte-l1-1-0.dll?

api-ms-win-crt-multibyte-l1-1-0.dll is a Dynamic Link Library file that ships with the Universal C Runtime from Microsoft. Programs link against it at runtime; when it's missing or the wrong version, the program refuses to start with the "api-ms-win-crt-multibyte-l1-1-0.dll is missing" error.

Is it safe to download api-ms-win-crt-multibyte-l1-1-0.dll from a DLL website?

No. Stand-alone DLL download sites are the most common malware vector on Windows. Always install the official Universal C Runtime from Microsoft instead — it's free and signed.

Do I need the x86 or x64 version of api-ms-win-crt-multibyte-l1-1-0.dll?

Install both. 64-bit Windows still runs many 32-bit programs (especially games and older apps), and each architecture needs its own copy of api-ms-win-crt-multibyte-l1-1-0.dll.

Why does api-ms-win-crt-multibyte-l1-1-0.dll disappear after I fix it?

Three usual suspects: an outdated installer overwriting it on launch, a System Restore reverting the fix, or aggressive antivirus quarantining it as a false positive. Check Defender's protection history first.

λ DLL Errors

api-ms-win-crt-multibyte-l1-1-0.dll is missing — How to fix it on Windows 11 (2026)

If Windows shows you "api-ms-win-crt-multibyte-l1-1-0.dll is missing from your computer" when you launch a game or program, the file api-ms-win-crt-multibyte-l1-1-0.dll is part of the Universal C Runtime and is almost always fixed by reinstalling that package. This guide walks you through the safe fixes — in the right order.

Time: 10 min
Difficulty: easy
Applies to: Windows 11, Windows 10
Updated: May 25, 2026

Error message

The program can't start because api-ms-win-crt-multibyte-l1-1-0.dll is missing from your computer. Try reinstalling the program to fix this problem.

Symptoms

▸Error popup: "The program can't start because api-ms-win-crt-multibyte-l1-1-0.dll is missing from your c…"
▸a game or program refuses to launch and immediately closes
▸Event Viewer logs "Faulting module name: api-ms-win-crt-multibyte-l1-1-0.dll"
▸Reinstalling the program does not fix the error on its own

Likely causes

▸The Universal C Runtime is not installed (or only one architecture is)
▸A recent Windows update or program installer corrupted api-ms-win-crt-multibyte-l1-1-0.dll
▸Antivirus quarantined api-ms-win-crt-multibyte-l1-1-0.dll as a false positive
▸An older program installed an obsolete copy of api-ms-win-crt-multibyte-l1-1-0.dll into its folder

How to fix it — step by step

01
Reinstall the Universal C Runtime
api-ms-win-crt-multibyte-l1-1-0.dll ships with the Universal C Runtime from Microsoft. Uninstall any existing copy from Settings → Apps, then download the latest x64 and x86 installers from the official Microsoft site (link) and install both. Most api-ms-win-crt-multibyte-l1-1-0.dll errors stop here.
02
Run System File Checker
Open PowerShell as Administrator and run the command below. SFC verifies and repairs protected Windows files, including most system-provided DLLs.
```
sfc /scannow
```
03
Repair the Windows component store with DISM
If SFC reports unrepairable files, repair the underlying Windows image first, then re-run SFC.
```
DISM /Online /Cleanup-Image /RestoreHealth
```
04
Reinstall the program that throws the error
If the error appears only when launching a game or program, that program installed its own copy of api-ms-win-crt-multibyte-l1-1-0.dll into its install folder. Uninstall it through Settings → Apps, restart Windows, then reinstall from the official source.
05
Check for malware
Malware often masquerades as a missing DLL. Run a full scan with Windows Defender (Windows Security → Virus & threat protection → Scan options → Full scan) before downloading any DLL from a third-party site.
06
Last resort: restore api-ms-win-crt-multibyte-l1-1-0.dll from a clean Windows install
If every other step failed, copy api-ms-win-crt-multibyte-l1-1-0.dll from C:\Windows\System32\ on another Windows 11 PC of the same architecture (x64 to x64) and the same build. Never download standalone DLLs from "DLL repositories" — they are the #1 vector for adware on Windows.

Frequently Asked Questions

Related fixes

DLLs

api-ms-win-crt-multibyte-l1-1-0.dll is missing — How to fix it on Windows 11 (2026)

How to fix it — step by step

Reinstall the Universal C Runtime

Run System File Checker

Repair the Windows component store with DISM

Reinstall the program that throws the error

Check for malware

Last resort: restore api-ms-win-crt-multibyte-l1-1-0.dll from a clean Windows install

Frequently Asked Questions

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