ucrtbase.dll: download the file and fix the error

32-bit and 64-bit Universal C Runtime (Windows) Scanned by antivirus

ucrtbase.dll is a file of the Windows Universal C Runtime (UCRT), used by programs compiled with Visual C++ 2015 and later. Its official description: “Microsoft® C Runtime Library”, by Microsoft Corporation.

If it is missing or damaged, Windows displays for example: “The program can't start because ucrtbase.dll is missing from your computer.” Two methods can fix the error, below.

Method 1 · quick · about 1 minute

Download only ucrtbase.dll

Ideal if only this file is reported missing: you replace a single file, without reinstalling anything.

⇓ Download the 64-bit version ⇓ Download the 32-bit version .zip file: the DLL + its instructions · downloaded 5,618 times

Which version should you choose? The one that matches the program showing the error, not Windows: a 32-bit game or program needs the 32-bit DLL, even on 64-bit Windows. If in doubt, try the 64-bit version first, then the 32-bit one if the error persists or becomes “0xc000007b”.

Version: 10.0.14393.0 (64-bit)10.0.17134.12 (32-bit)
Size: 998.92 KB (64-bit)1.17 MB (32-bit)
Architecture: 64-bit (x64)32-bit (x86)
Publisher: Microsoft Corporation

Then:

Extract ucrtbase.dll from the zip file and copy it to the folder of the program showing the error (where its .exe file is).
Still getting the error? Copy it to C:\Windows\System32 (64-bit DLL) or C:\Windows\SysWOW64 (32-bit DLL on 64-bit Windows), then restart.

SHA-256 (64-bit): 780b1b52574fac8a5219e9496d400fa0048618227f3d826663bad4d1ad12fcd4 · Check on VirusTotal
SHA-256 (32-bit): 6f8f05993b8a25cadf5e301e58194c4d23402e467229b12e40956e4f128588b3 · Check on VirusTotal · Product: Microsoft® Windows® Operating System

Method 2 · complete · official method · 10 minutes

Update Windows and reinstall Visual C++ 2015-2022

This file is built into Windows 10 and 11. On Windows 7 and 8.1, it is installed by Windows Update or by Microsoft’s Visual C++ 2015-2022 package.

Microsoft.com: Visual C++ 64-bit Microsoft.com: Visual C++ 32-bit

Run Windows Update and install all available updates.
Install both Visual C++ 2015-2022 packages (64-bit and 32-bit), then restart your computer.

Complete guide: Visual C++ errors (msvcp, msvcr, vcruntime)

Error messages related to ucrtbase.dll

The program can't start because ucrtbase.dll is missing.
Failed to load ucrtbase.dll
Error loading ucrtbase.dll. The specified module could not be found.

Why does this error occur?

Windows 7 or 8.1 not up to date: the Universal C Runtime is not included out of the box.
Visual C++ 2015-2022 missing or damaged.
Damaged system file on Windows 10 or 11.

Files of the same family (Universal C Runtime)

api-ms-win-crt-heap-l1-1-0.dll api-ms-win-crt-math-l1-1-0.dll api-ms-win-crt-runtime-l1-1-0.dll api-ms-win-crt-stdio-l1-1-0.dll api-ms-win-crt-string-l1-1-0.dll msvcp140.dll vcruntime140.dll

Frequently asked questions

Why “api-ms-win-crt” files?

They are small redirection files to ucrtbase.dll. Windows and the Visual C++ 2015-2022 package install them together; it is rarely useful to copy them one by one.