ucrtbase.dll
This file belongs to Universal C Runtime, via Windows Update. Install that package and the DLL arrives with it, in the right place and correctly registered.
Do not download this DLL on its own
Searching for a missing DLL by name leads to sites that hand you that single file. It is one of the oldest and most effective malware delivery methods there is, and a system DLL from an unknown source is indistinguishable from a deliberately modified one. There is never a legitimate reason to obtain a runtime component that way.
What it is
The core of the Universal C Runtime, the C standard library that Microsoft moved into Windows itself with Windows 10. It is serviced through Windows Update rather than being a normal redistributable file.
Where you see it: Application crashes naming ucrtbase.dll as the faulting module, and startup failures on Windows installations that are behind on updates.
Run Windows Update first, because on Windows 10 and 11 this file belongs to the operating system. If a crash names ucrtbase.dll as the faulting module, that usually points at the application misusing the runtime rather than at a damaged file, so also try repairing or reinstalling the program. The Visual C++ redistributable installs the compatible pieces on older systems.
Install Universal C Runtime, via Windows Update
The official package, with the download URL Microsoft declares and the SHA-256 of every installer so you can verify it before running.
- Microsoft Visual C++ v14 Redistributable (x64)v14.51.36247.0 · 2 hashed installers100
- Microsoft Visual C++ v14 Redistributable (x86)v14.51.36247.0 · 1 hashed installer100
After downloading you can check the file against our index to confirm it is the installer the publisher shipped.