diff --git a/crates/pm/src/service/install.rs b/crates/pm/src/service/install.rs
index d39541d20..0bee847d4 100644
--- a/crates/pm/src/service/install.rs
+++ b/crates/pm/src/service/install.rs
@@ -136,13 +136,15 @@ pub async fn install_packages(
                         package.optional == Some(true) || package.dev_optional == Some(true);
 
                     let task = tokio::spawn(async move {
-                        if !clone_package_once(&name, &version, &resolved, &target_path).await {
+                        if let Err(e) =
+                            clone_package_once(&name, &version, &resolved, &target_path).await
+                        {
                             if is_optional {
                                 tracing::warn!("Optional dependency {name} failed (ignored)");
                                 PROGRESS_BAR.inc(1);
                                 return Ok(());
                             }
-                            anyhow::bail!("{name} clone failed");
+                            return Err(e);
                         }
                         PROGRESS_BAR.inc(1);
                         log_progress(&format!("{name} resolved"));
diff --git a/crates/pm/src/service/pipeline/worker.rs b/crates/pm/src/service/pipeline/worker.rs
index c636971f3..af9348c8f 100644
--- a/crates/pm/src/service/pipeline/worker.rs
+++ b/crates/pm/src/service/pipeline/worker.rs
@@ -59,7 +59,9 @@ pub fn start_workers(channels: PipelineChannels, cwd: PathBuf) -> PipelineHandle
                 if let Some(ref parent) = parent_path {
                     wait_clone_if_pending(&parent.to_string_lossy()).await;
                 }
-                clone_package_once(&name, &version, &tarball_url, &target).await;
+                if let Err(e) = clone_package_once(&name, &version, &tarball_url, &target).await {
+                    tracing::debug!("Pipeline pre-clone failed for {name}@{version}: {e:#}");
+                }
             });
         }
     });
diff --git a/crates/pm/src/util/cloner.rs b/crates/pm/src/util/cloner.rs
index 8a6ebc1ac..2ffbcb4df 100644
--- a/crates/pm/src/util/cloner.rs
+++ b/crates/pm/src/util/cloner.rs
@@ -13,8 +13,16 @@ use super::retry::create_retry_strategy;
 use crate::fs;
 
 /// Global clone cache shared between pipeline and install phases.
-/// Key: target path, Value: ()
-static CLONE_CACHE: Lazy<OnceMap<String, ()>> = Lazy::new(OnceMap::new);
+///
+/// Key: normalized target path. Install (`cwd.join("node_modules/foo")` →
+/// forward slashes) and pipeline (`Path::join` injects backslashes on
+/// Windows) produce the same logical target with different separators;
+/// without normalization OnceMap sees them as distinct keys, dedup fails,
+/// and concurrent tasks race on the same destination — manifesting as
+/// `ERROR_SHARING_VIOLATION` (os error 32) on Windows. `PathBuf` from
+/// `Path::components().collect()` parses both separators uniformly and
+/// rebuilds with the OS-preferred one, giving a stable key.
+static CLONE_CACHE: Lazy<OnceMap<PathBuf, ()>> = Lazy::new(OnceMap::new);
 
 /// Number of clones completed.
 static CLONE_COUNT: AtomicUsize = AtomicUsize::new(0);
@@ -24,12 +32,25 @@ pub fn clone_count() -> usize {
     CLONE_COUNT.load(Ordering::Relaxed)
 }
 
+/// Normalize a target path into the canonical key used by `CLONE_CACHE`.
+#[cfg(windows)]
+fn cache_key(target_path: &Path) -> PathBuf {
+    target_path.components().collect()
+}
+
+#[cfg(not(windows))]
+fn cache_key(target_path: &Path) -> PathBuf {
+    target_path.to_path_buf()
+}
+
 /// Wait for a pending clone at the given target path to complete (if any).
 ///
 /// Used by the pipeline clone worker to ensure parent packages are
 /// cloned before their children.
 pub async fn wait_clone_if_pending(target_path: &str) {
-    CLONE_CACHE.wait_if_pending(&target_path.to_string()).await;
+    CLONE_CACHE
+        .wait_if_pending(&cache_key(Path::new(target_path)))
+        .await;
 }
 
 /// Clone a package to target path, downloading to cache first if needed.
@@ -41,8 +62,9 @@ pub async fn clone_package_once(
     version: &str,
     tarball_url: &str,
     target_path: &Path,
-) -> bool {
-    let key = target_path.to_string_lossy().to_string();
+) -> Result<()> {
+    let key = cache_key(target_path);
+    let err_label = format!("{name}@{version}");
     let name = name.to_string();
     let version = version.to_string();
     let tarball_url = tarball_url.to_string();
@@ -59,7 +81,7 @@ pub async fn clone_package_once(
                 .await
                 .inspect_err(|e| {
                     tracing::warn!(
-                        "Clone failed: {}@{} to {}: {}",
+                        "Clone failed: {}@{} to {}: {:#}",
                         name,
                         version,
                         target_path.display(),
@@ -73,7 +95,8 @@ pub async fn clone_package_once(
             Some(())
         })
         .await
-        .is_some()
+        .map(|_| ())
+        .ok_or_else(|| anyhow::anyhow!("clone {err_label} failed (see warning log for details)"))
 }
 
 #[cfg(target_os = "macos")]
@@ -438,6 +461,20 @@ mod tests {
 
     use super::*;
 
+    #[cfg(windows)]
+    #[test]
+    fn cache_key_normalizes_path_separators() {
+        // install.rs joins lockfile-derived strings (forward slashes) while
+        // pipeline workers go through `Path::join` (backslashes). Both must
+        // produce the same OnceMap key — otherwise concurrent clones race
+        // and Windows raises ERROR_SHARING_VIOLATION.
+        let forward = cache_key(Path::new("node_modules/@scope/pkg/node_modules/dep"));
+        let backward = cache_key(Path::new("node_modules\\@scope\\pkg\\node_modules\\dep"));
+        let mixed = cache_key(Path::new("node_modules/@scope/pkg\\node_modules\\dep"));
+        assert_eq!(forward, backward);
+        assert_eq!(forward, mixed);
+    }
+
     async fn create_test_file(dir: &Path, name: &str, content: &[u8]) -> Result<PathBuf> {
         let path = dir.join(name);
         let mut file = fs::File::create(&path).await?;
diff --git a/e2e/utoo-pm.ps1 b/e2e/utoo-pm.ps1
index fa9cae30b..c8b77ddc5 100644
--- a/e2e/utoo-pm.ps1
+++ b/e2e/utoo-pm.ps1
@@ -306,6 +306,40 @@ finally {
     Remove-Item -Recurse -Force $antdxDir -ErrorAction SilentlyContinue
 }
 
+# Case: pnpm migration (eggjs/egg)
+Write-Yellow "Case: pnpm migration (eggjs/egg)"
+$eggDir = Join-Path $env:TEMP "utoo-e2e-egg-$(Get-Random)"
+try {
+    git clone --branch next --single-branch --depth 1 https://github.com/eggjs/egg.git $eggDir
+    Push-Location $eggDir
+
+    utoo install --from pnpm --ignore-scripts --registry=https://registry.npmjs.org
+    if ($LASTEXITCODE -ne 0) { throw "utoo install --from pnpm failed for eggjs/egg" }
+
+    # Verify workspaces field was added to package.json
+    node -e "const pkg = require('./package.json'); const ws = pkg.workspaces; if (!ws || !Array.isArray(ws)) throw new Error('workspaces not set'); if (!ws.includes('packages/*')) throw new Error('missing packages/*'); console.log('  workspaces:', ws.length, 'patterns');"
+    if ($LASTEXITCODE -ne 0) { throw "workspaces field verification failed" }
+
+    # Verify overrides were added
+    node -e "const pkg = require('./package.json'); if (!pkg.overrides) throw new Error('overrides not set'); if (!pkg.overrides.vite) throw new Error('vite override missing'); console.log('  overrides:', Object.keys(pkg.overrides).length, 'entries');"
+    if ($LASTEXITCODE -ne 0) { throw "overrides field verification failed" }
+
+    # Verify .utoo.toml was created with catalogs
+    if (-not (Test-Path ".utoo.toml")) { throw ".utoo.toml not created" }
+    $tomlContent = Get-Content .utoo.toml -Raw
+    if ($tomlContent -notmatch 'lodash') { throw "catalog missing lodash" }
+    if ($tomlContent -notmatch 'path-to-regexp') { throw "named catalog missing" }
+
+    # Verify node_modules was created (install ran successfully)
+    if (-not (Test-Path "node_modules")) { throw "node_modules not created" }
+
+    Write-Green "PASS: pnpm migration (eggjs/egg)"
+}
+finally {
+    Pop-Location
+    Remove-Item -Recurse -Force $eggDir -ErrorAction SilentlyContinue
+}
+
 # Case: install-node + esbuild postinstall
 Write-Yellow "Case: install-node + esbuild"
 $esbuildDir = Join-Path $env:TEMP "utoo-e2e-esbuild-$(Get-Random)"