diff --git a/pkgs/tools/package-management/nix/modular/src/libstore/package.nix b/pkgs/tools/package-management/nix/modular/src/libstore/package.nix
index 80f95ea3981d..e506383c2a09 100644
--- a/pkgs/tools/package-management/nix/modular/src/libstore/package.nix
+++ b/pkgs/tools/package-management/nix/modular/src/libstore/package.nix
@@ -73,6 +73,9 @@ mkMesonLibrary (finalAttrs: {
     nlohmann_json
   ];
 
+  # Don't use the default name "build": that conflicts with an existing directory.
+  mesonBuildDir = "meson-build-dir";
+
   mesonFlags = [
     (lib.mesonEnable "seccomp-sandboxing" stdenv.hostPlatform.isLinux)
     (lib.mesonBool "embedded-sandbox-shell" embeddedSandboxShell)