diff --git a/backend/managers/javaManager.js b/backend/managers/javaManager.js
index c2ebf85..48e34b2 100644
--- a/backend/managers/javaManager.js
+++ b/backend/managers/javaManager.js
@@ -106,6 +106,23 @@ function getBundledJavaPath(jreDir = JRE_DIR) {
     }
   }
 
+  // Fallback: check for nested JRE directory (e.g. jdk-25.0.2+10-jre/bin/java)
+  // This happens when flattenJREDir fails due to EPERM/EACCES on Windows
+  try {
+    if (fs.existsSync(jreDir)) {
+      const entries = fs.readdirSync(jreDir, { withFileTypes: true });
+      for (const entry of entries) {
+        if (entry.isDirectory() && entry.name !== 'bin' && entry.name !== 'lib') {
+          const nestedCandidate = path.join(jreDir, entry.name, 'bin', JAVA_EXECUTABLE);
+          if (fs.existsSync(nestedCandidate)) {
+            console.log(`[JRE] Using nested Java path: ${nestedCandidate}`);
+            return nestedCandidate;
+          }
+        }
+      }
+    }
+  } catch (_) { /* ignore */ }
+
   return null;
 }
 
@@ -409,7 +426,7 @@ function extractTarGz(tarGzPath, dest) {
 function flattenJREDir(jreLatest) {
   try {
     const entries = fs.readdirSync(jreLatest, { withFileTypes: true });
-    
+
     if (entries.length !== 1 || !entries[0].isDirectory()) {
       return;
     }
@@ -420,12 +437,48 @@ function flattenJREDir(jreLatest) {
     for (const file of files) {
       const oldPath = path.join(nested, file.name);
       const newPath = path.join(jreLatest, file.name);
-      fs.renameSync(oldPath, newPath);
+      try {
+        fs.renameSync(oldPath, newPath);
+      } catch (renameErr) {
+        if (renameErr.code === 'EPERM' || renameErr.code === 'EACCES' || renameErr.code === 'EBUSY') {
+          console.log(`[JRE] Rename failed for ${file.name} (${renameErr.code}), using copy fallback`);
+          copyRecursiveSync(oldPath, newPath);
+        } else {
+          throw renameErr;
+        }
+      }
     }
 
-    fs.rmSync(nested, { recursive: true, force: true });
+    try {
+      fs.rmSync(nested, { recursive: true, force: true });
+    } catch (rmErr) {
+      console.log('[JRE] Could not remove nested JRE dir (non-critical):', rmErr.message);
+    }
   } catch (err) {
-    console.log('Notice: could not restructure Java directory:', err.message);
+    console.error('[JRE] Failed to restructure Java directory:', err.message);
+    // Last resort: check if java exists in a nested subdir and skip flatten
+    try {
+      const entries = fs.readdirSync(jreLatest, { withFileTypes: true });
+      const nestedDir = entries.find(e => e.isDirectory() && e.name !== 'bin' && e.name !== 'lib');
+      if (nestedDir) {
+        const nestedBin = path.join(jreLatest, nestedDir.name, 'bin', process.platform === 'win32' ? 'java.exe' : 'java');
+        if (fs.existsSync(nestedBin)) {
+          console.log(`[JRE] Java found in nested dir: ${nestedDir.name}, leaving structure as-is`);
+        }
+      }
+    } catch (_) { /* ignore */ }
+  }
+}
+
+function copyRecursiveSync(src, dest) {
+  const stat = fs.statSync(src);
+  if (stat.isDirectory()) {
+    fs.mkdirSync(dest, { recursive: true });
+    for (const child of fs.readdirSync(src)) {
+      copyRecursiveSync(path.join(src, child), path.join(dest, child));
+    }
+  } else {
+    fs.copyFileSync(src, dest);
   }
 }