Cmake Error File Download Hash Mismatch [patched] Guide

The URL might be pointing to a login page or a "404 Not Found" HTML page instead of the actual archive. How to Fix the Error 1. Verify the Current Hash

A glitch in the network connection resulted in an incomplete or corrupted file.

A Man-in-the-Middle (MitM) attack could be serving a malicious version of the file. cmake error file download hash mismatch

The developer of the remote dependency updated the file (e.g., a new release) but kept the same filename, changing the hash.

By strictly matching the URL_HASH to the file content, you ensure that every developer on your team builds against the exact same source code, maintaining project integrity. The URL might be pointing to a login

Sometimes CMake keeps a corrupted partial download in its internal build directory. Delete your build folder.

Always point to a specific tag or commit hash rather than a "latest" or "master" branch link. A Man-in-the-Middle (MitM) attack could be serving a

Use FetchContent for modern CMake projects, as it integrates better with the build system than ExternalProject_Add . Example Configuration

If you are using an older hash like MD5, switch to . It is more secure and less prone to collisions. Best Practices for Downloads To avoid this error in the future, follow these standards:

The cmake error file download hash mismatch is a common roadblock when using CMake’s ExternalProject or FetchContent modules. It occurs when the file downloaded from a remote URL does not match the cryptographic checksum (SHA256, MD5, etc.) specified in your CMakeLists.txt file. Why the Error Happens