diff --git a/.gitignore b/.gitignore
index c908d25..2e36d3e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,7 +1,5 @@
 # Lean
 /.lake
-# Local clone for Lake build
-/blake3
 
 # Rust
 **/target
diff --git a/flake.nix b/flake.nix
index b8b4178..67f3a2c 100644
--- a/flake.nix
+++ b/flake.nix
@@ -76,8 +76,10 @@
           disableCargoBuild = ''
             substituteInPlace lakefile.lean --replace-fail 'proc { cmd := "cargo"' '--proc { cmd := "cargo"'
           '';
+          # `-fn` so it overwrites the symlink rsynced in from a prior stage's `.lake`
           linkBlake3Src = ''
-            ln -s ${blake3.outPath} ./blake3
+            mkdir -p .lake
+            ln -sfn ${blake3.outPath} .lake/blake3-source
           '';
           # Copy the `blake3_rs` static lib from Crane to `target/release` so Lake can use it
           linkRustLib = ''
@@ -128,9 +130,6 @@
             buildLibrary = true;
             postPatch = disableGitClone;
             preConfigure = linkBlake3Src;
-            postInstall = ''
-              cp -rP ./blake3 $out
-            '';
           };
 
           blake3Rust = lake2nix.mkPackage {
diff --git a/lakefile.lean b/lakefile.lean
index e8900fc..c8a5fe4 100644
--- a/lakefile.lean
+++ b/lakefile.lean
@@ -15,7 +15,11 @@ abbrev blake3RepoURL := "https://github.com/BLAKE3-team/BLAKE3"
 abbrev blake3RepoTag := "1.8.7"
 
 target cloneBlake3 pkg : GitRepo := do
-  let repoDir : GitRepo := pkg.dir / "blake3"
+  -- Under `.lake` rather than the package root: it is already untracked, and a
+  -- sibling `blake3` directory would collide with `Blake3` on case-insensitive
+  -- filesystems (macOS, Windows). `lake clean` only clears `.lake/build`, so the
+  -- clone survives.
+  let repoDir : GitRepo := pkg.lakeDir / "blake3-source"
 
   -- Clone if it hasn't already been cloned
   let alreadyCloned ← repoDir.dir.pathExists