diff --git a/.github/workflows/publish_pypi.yml b/.github/workflows/publish_pypi.yml
index 2f5c1ab..37449b0 100644
--- a/.github/workflows/publish_pypi.yml
+++ b/.github/workflows/publish_pypi.yml
@@ -96,7 +96,7 @@ jobs:
             mv ~/osxcross ~/.osxcross
           fi
 
-      - name: Prefer system Eigen in the libczirw cmake build
+      - name: Tune the libczirw-sys cmake build (system Eigen, dynamic CRT)
         run: |
           # libczirw-sys cmake build clones Eigen3 from gitlab.com (ExternalProject);
           # that clone is flaky on this runner (it is the only git-based network step
@@ -106,10 +106,16 @@ jobs:
           # variable from the environment, so a cmake shim injects it (-D); the shim is
           # scoped to invocations that look like the libczi configure (no-op for
           # --build / --version / other uses).
+          # the override also aligns the msvc CRT: libCZI forces the static runtime
+          # (/MT) while the rest of the build (Rust std, cc-compiled vendored libs,
+          # /defaultlib:msvcrt) is dynamic (/MD), and lld-link rejects the mix with
+          # /failifmismatch:RuntimeLibrary. no effect on the non-windows builds.
           mkdir -p /root/ci-shims
           cat > /root/cm-override-libczi.cmake <<'CMAKEEOF'
           if (CMAKE_PROJECT_NAME STREQUAL "libCZI")
             set(LIBCZI_BUILD_PREFER_EXTERNALPACKAGE_EIGEN3 ON CACHE BOOL "" FORCE)
+            set(LIBCZI_DO_NOT_SET_MSVC_RUNTIME_LIBRARY ON CACHE BOOL "" FORCE)
+            set(CMAKE_MSVC_RUNTIME_LIBRARY "MultiThreadedDLL$<$<CONFIG:Debug>:Debug>" CACHE STRING "" FORCE)
           endif()
           CMAKEEOF
           cat > /root/ci-shims/cmake <<'SHIMEOF'