diff --git a/apps/web/product-isolation.ts b/apps/web/product-isolation.ts
index ee78af5ce9..c716329078 100644
--- a/apps/web/product-isolation.ts
+++ b/apps/web/product-isolation.ts
@@ -33,7 +33,12 @@ export function productWebBundleIsolation(repository: string, webRoot: string):
   return [{
     name: 'dsh-product-web-chunk-inputs',
     apply: 'build',
-    generateBundle: { order: 'pre', handler(_options, bundle) { inputs.captureChunks(bundle) } },
+    generateBundle: {
+      order: 'pre',
+      handler(_options, bundle) {
+        if (!dependencyAnalysis) inputs.captureChunks(bundle)
+      },
+    },
   }, {
     name: 'dsh-product-web-bundle-isolation',
     apply: 'build',
diff --git a/scripts/browser-bundled-externals.spec.ts b/scripts/browser-bundled-externals.spec.ts
index 549f2bded5..0607c99ae5 100644
--- a/scripts/browser-bundled-externals.spec.ts
+++ b/scripts/browser-bundled-externals.spec.ts
@@ -1,13 +1,30 @@
 import { existsSync, mkdirSync, mkdtempSync, readFileSync, rmSync, symlinkSync, unlinkSync, writeFileSync } from 'node:fs'
+import { createRequire } from 'node:module'
 import { tmpdir } from 'node:os'
 import { dirname, join, resolve } from 'node:path'
-import { afterEach, describe, expect, it } from 'vitest'
+import { afterEach, describe, expect, it, vi } from 'vitest'
 import { browserBundledExternals, browserPackageOfFile, browserSourceAliases } from './browser-bundled-externals.ts'
 
+const filesystem = vi.hoisted(() => ({ preservedAlias: undefined as string | undefined }))
+vi.mock('node:fs', async (importOriginal) => {
+  const actual = await importOriginal<typeof import('node:fs')>()
+  return {
+    ...actual,
+    realpathSync: Object.assign((...args: Parameters<typeof actual.realpathSync>) => {
+      // Windows' JavaScript realpath can retain an 8.3 alias that Vite's native resolution expands.
+      if (typeof args[0] === 'string' && args[0] === filesystem.preservedAlias) return args[0]
+      return actual.realpathSync(...args)
+    }, { native: actual.realpathSync.native }),
+  }
+})
+
 const roots: string[] = []
+const dependencyLinks: string[] = []
 const repositoryRoot = resolve(import.meta.dirname, '..')
 
 afterEach(() => {
+  filesystem.preservedAlias = undefined
+  for (const link of dependencyLinks.splice(0)) unlinkSync(link)
   for (const root of roots.splice(0)) rmSync(root, { recursive: true, force: true })
 })
 
@@ -78,7 +95,10 @@ describe('browser dependency discovery', () => {
     await expect(browserBundledExternals(root)).rejects.toThrow('has no browser build config')
   })
 
-  it.each([false, true])('follows shell aliases, CSS and lazy imports without writing output (symlinked root: %s)', async (linked) => {
+  it.each([
+    ['Rollup', false, false], ['Rollup', true, false], ['Rollup', true, true],
+    ['Rolldown', false, false], ['Rolldown', true, false], ['Rolldown', true, true],
+  ] as const)('follows shell aliases, CSS and lazy imports without writing output (%s, symlinked root: %s, retained alias: %s)', async (bundler, linked, preserveAlias) => {
     const root = fixture()
     library(root, 'shell-lib')
     library(root, 'lazy-lib')
@@ -96,7 +116,13 @@ describe('browser dependency discovery', () => {
     ].join('\n'))
     const app = join(root, 'apps/web')
     write(root, 'apps/web/package.json', '{"name":"@fixture/web","type":"module","exports":{"./dist/*":"./dist/*"}}')
-    symlinkSync(resolve(repositoryRoot, 'apps/web/node_modules'), join(app, 'node_modules'), 'junction')
+    const owner = bundler === 'Rollup' ? resolve(repositoryRoot, 'apps/web/package.json')
+      : createRequire(resolve(repositoryRoot, 'package.json')).resolve('vitest/package.json')
+    const viteDirectory = dirname(createRequire(owner).resolve('vite/package.json'))
+    const viteLink = join(app, 'node_modules/vite')
+    mkdirSync(dirname(viteLink), { recursive: true })
+    symlinkSync(viteDirectory, viteLink, 'junction')
+    dependencyLinks.push(viteLink)
     write(root, 'apps/web/index.html', '<script type="module" src="./main.ts"></script>')
     write(root, 'apps/web/main.ts', 'import { output, lazy } from "@fixture/static"; console.log(output); void lazy()')
     write(root, 'apps/web/vite.config.ts', `
@@ -104,7 +130,13 @@ describe('browser dependency discovery', () => {
       export default ({ mode }) => {
         if (mode !== 'production') throw new Error('notice discovery must use the production build mode')
         return {
-          plugins: productWebBundleIsolation(${JSON.stringify(root)}, ${JSON.stringify(app)}),
+          plugins: [...productWebBundleIsolation(${JSON.stringify(root)}, ${JSON.stringify(app)}), {
+            name: 'fixture-bundler-engine',
+            generateBundle() {
+              const actual = typeof this.meta.rolldownVersion === 'string' ? 'Rolldown' : 'Rollup'
+              if (actual !== ${JSON.stringify(bundler)}) throw new Error('unexpected bundler: ' + actual)
+            },
+          }],
           build: { rollupOptions: { input: { index: ${JSON.stringify(join(app, 'index.html'))}, preview: "missing-preview.ts" } } }
         }
       }
@@ -113,9 +145,11 @@ describe('browser dependency discovery', () => {
 
     const scanRoot = linked ? join(fixture(), 'linked') : root
     if (linked) symlinkSync(root, scanRoot, 'junction')
+    if (preserveAlias) filesystem.preservedAlias = scanRoot
     try {
       expect(await browserBundledExternals(scanRoot)).toEqual(new Set(['shell-lib', 'lazy-lib', 'asset-lib']))
     } finally {
+      filesystem.preservedAlias = undefined
       if (linked) unlinkSync(scanRoot)
     }
     expect(readFileSync(join(app, 'dist/sentinel.txt'), 'utf8')).toBe('untouched')
diff --git a/scripts/browser-bundled-externals.ts b/scripts/browser-bundled-externals.ts
index 8675fdd006..7669a234ea 100644
--- a/scripts/browser-bundled-externals.ts
+++ b/scripts/browser-bundled-externals.ts
@@ -166,8 +166,8 @@ async function collectShell(
  * @returns Names of distributed browser inputs, excluding workspace packages and erased types.
  */
 export async function browserBundledExternals(root: string): Promise<Set<string>> {
-  // Vite resolves HTML inputs to real paths, so its root must use the same spelling.
-  root = realpathSync(root)
+  // Vite resolves HTML through native realpath, including Windows 8.3 alias expansion.
+  root = realpathSync.native(root)
   const manifests = new Map<string, Manifest>()
   for (const glob of ['packages/*/*/package.json', 'vendor/*/package.json']) {
     for (const path of globSync(glob, { cwd: root }).sort()) {
diff --git a/scripts/web-product-bundle-isolation.spec.ts b/scripts/web-product-bundle-isolation.spec.ts
index b5e14dab94..a3c9005a02 100644
--- a/scripts/web-product-bundle-isolation.spec.ts
+++ b/scripts/web-product-bundle-isolation.spec.ts
@@ -25,7 +25,8 @@ const vite = createRequire(new URL('../apps/web/package.json', import.meta.url))
 }
 
 function fixture() {
-  const root = realpathSync(mkdtempSync(join(tmpdir(), 'dsh-web-bundle-isolation-')))
+  // Vite resolves inputs with native realpath, which expands Windows short names.
+  const root = realpathSync.native(mkdtempSync(join(tmpdir(), 'dsh-web-bundle-isolation-')))
   const web = join(root, 'apps/web')
   const links: string[] = []
   onTestFinished(() => {
@@ -89,7 +90,12 @@ describe('default Web bundle input isolation', () => {
   })
 
   it('allows experimental code in the separately emitted preview entry', async () => {
-    await expect(fixture().run()).resolves.toBeDefined()
+    await expect(fixture().run()).resolves.toMatchObject({
+      output: expect.arrayContaining([
+        expect.objectContaining({ type: 'asset', fileName: 'index.html' }),
+        expect.objectContaining({ type: 'chunk', name: 'bootstrap' }),
+      ]) as unknown,
+    })
   })
 
   it.each([