diff --git a/packages/docusaurus-mdx-loader/src/remark/transformImage/__tests__/index.test.ts b/packages/docusaurus-mdx-loader/src/remark/transformImage/__tests__/index.test.ts
index fec6f2980b..f7acabd6a5 100644
--- a/packages/docusaurus-mdx-loader/src/remark/transformImage/__tests__/index.test.ts
+++ b/packages/docusaurus-mdx-loader/src/remark/transformImage/__tests__/index.test.ts
@@ -11,7 +11,6 @@ import mdx from 'remark-mdx';
 import vfile from 'to-vfile';
 import plugin from '../index';
 import headings from '../../headings/index';
-import {posixPath} from '@docusaurus/utils';
 
 const processFixture = async (name, options) => {
   const filePath = path.join(__dirname, `__fixtures__/${name}.md`);
@@ -24,7 +23,8 @@ const processFixture = async (name, options) => {
 
   return result
     .toString()
-    .replace(new RegExp(posixPath(process.cwd()), 'g'), '[CWD]');
+    .replace(/\\\\/g, '/')
+    .replace(new RegExp(process.cwd().replace(/\\/g, '/'), 'g'), '[CWD]');
 };
 
 const staticDirs = [
diff --git a/packages/docusaurus-mdx-loader/src/remark/transformLinks/__tests__/index.test.ts b/packages/docusaurus-mdx-loader/src/remark/transformLinks/__tests__/index.test.ts
index 6129510b41..d48a014d19 100644
--- a/packages/docusaurus-mdx-loader/src/remark/transformLinks/__tests__/index.test.ts
+++ b/packages/docusaurus-mdx-loader/src/remark/transformLinks/__tests__/index.test.ts
@@ -11,7 +11,6 @@ import mdx from 'remark-mdx';
 import vfile from 'to-vfile';
 import plugin from '..';
 import transformImage from '../../transformImage';
-import {posixPath} from '@docusaurus/utils';
 
 const processFixture = async (name: string, options?) => {
   const filePath = path.join(__dirname, `__fixtures__/${name}.md`);
@@ -33,7 +32,8 @@ const processFixture = async (name: string, options?) => {
 
   return result
     .toString()
-    .replace(new RegExp(posixPath(process.cwd()), 'g'), '[CWD]');
+    .replace(/\\\\/g, '/')
+    .replace(new RegExp(process.cwd().replace(/\\/g, '/'), 'g'), '[CWD]');
 };
 
 describe('transformAsset plugin', () => {
diff --git a/packages/docusaurus-utils/src/escapePath.ts b/packages/docusaurus-utils/src/escapePath.ts
index d53a52a7b3..b0ded61ccb 100644
--- a/packages/docusaurus-utils/src/escapePath.ts
+++ b/packages/docusaurus-utils/src/escapePath.ts
@@ -11,9 +11,9 @@
  * For example, this would fail due to unescaped \: `<img src={require('${filePath}')} />`
  * But this would work: `<img src={require('${escapePath(filePath)}')} />`
  *
- * Workaround for issue in posixPath, maybe we won't need it anymore soon?
- * https://github.com/facebook/docusaurus/issues/4730#issuecomment-833530370
- * https://github.com/sindresorhus/slash/pull/16#issuecomment-833528479
+ * posixPath can't be used in all cases, because forward slashes are only valid
+ * Windows paths when they don't contain non-ascii characters, and posixPath
+ * doesn't escape those that fail to be converted.
  */
 export function escapePath(str: string): string {
   const escaped = JSON.stringify(str);
diff --git a/packages/docusaurus-utils/src/posixPath.ts b/packages/docusaurus-utils/src/posixPath.ts
index 792356376e..bf3bf05c86 100644
--- a/packages/docusaurus-utils/src/posixPath.ts
+++ b/packages/docusaurus-utils/src/posixPath.ts
@@ -7,18 +7,20 @@
 
 /**
  * Convert Windows backslash paths to posix style paths.
- * E.g: endi\\lie -> endi/lie
+ * E.g: endi\lie -> endi/lie
  *
- * Looks like this code was originally copied from https://github.com/sindresorhus/slash/blob/main/index.js
+ * Returns original path if the posix counterpart is not valid Windows path.
+ * This makes the legacy code that uses posixPath safe; but also makes it less
+ * useful when you actually want a path with forward slashes (e.g. for URL)
  *
+ * Adopted from https://github.com/sindresorhus/slash/blob/main/index.js
  */
 export function posixPath(str: string): string {
   const isExtendedLengthPath = /^\\\\\?\\/.test(str);
 
-  // TODO not sure why we need this
-  // See https://github.com/sindresorhus/slash/pull/16#issuecomment-833528479
-  // See https://github.com/facebook/docusaurus/issues/4730#issuecomment-833530370
-  const hasNonAscii = /[^\u0000-\u0080]+/.test(str); // eslint-disable-line
+  // Forward slashes are only valid Windows paths when they don't contain non-ascii characters.
+  // eslint-disable-next-line no-control-regex
+  const hasNonAscii = /[^\u0000-\u0080]+/.test(str);
 
   if (isExtendedLengthPath || hasNonAscii) {
     return str;
diff --git a/packages/docusaurus-utils/src/webpackUtils.ts b/packages/docusaurus-utils/src/webpackUtils.ts
index 858b817588..87b1bb8f00 100644
--- a/packages/docusaurus-utils/src/webpackUtils.ts
+++ b/packages/docusaurus-utils/src/webpackUtils.ts
@@ -7,7 +7,7 @@
 
 import type {RuleSetRule} from 'webpack';
 import path from 'path';
-import {posixPath} from './posixPath';
+import {escapePath} from './escapePath';
 import {
   WEBPACK_URL_LOADER_LIMIT,
   OUTPUT_STATIC_ASSETS_DIR_NAME,
@@ -61,12 +61,12 @@ export function getFileLoaderUtils(): FileLoaderUtils {
     // Maybe with the ideal image plugin, all md images should be "ideal"?
     // This is used to force url-loader+file-loader on markdown images
     // https://webpack.js.org/concepts/loaders/#inline
-    inlineMarkdownImageFileLoader: `!${posixPath(
+    inlineMarkdownImageFileLoader: `!${escapePath(
       require.resolve('url-loader'),
     )}?limit=${urlLoaderLimit}&name=${fileLoaderFileName(
       'images',
-    )}&fallback=${posixPath(require.resolve('file-loader'))}!`,
-    inlineMarkdownLinkFileLoader: `!${posixPath(
+    )}&fallback=${escapePath(require.resolve('file-loader'))}!`,
+    inlineMarkdownLinkFileLoader: `!${escapePath(
       require.resolve('file-loader'),
     )}?name=${fileLoaderFileName('files')}!`,
   };
diff --git a/packages/docusaurus/src/server/__tests__/__snapshots__/routes.test.ts.snap b/packages/docusaurus/src/server/__tests__/__snapshots__/routes.test.ts.snap
index 03623c65b4..fa6b77131d 100644
--- a/packages/docusaurus/src/server/__tests__/__snapshots__/routes.test.ts.snap
+++ b/packages/docusaurus/src/server/__tests__/__snapshots__/routes.test.ts.snap
@@ -4,19 +4,19 @@ exports[`loadRoutes flat route config 1`] = `
 Object {
   "registry": Object {
     "component---theme-blog-list-pagea-6-a-7ba": Object {
-      "loader": "() => import(/* webpackChunkName: 'component---theme-blog-list-pagea-6-a-7ba' */ \\"@theme/BlogListPage\\")",
+      "loader": "() => import(/* webpackChunkName: 'component---theme-blog-list-pagea-6-a-7ba' */ '@theme/BlogListPage')",
       "modulePath": "@theme/BlogListPage",
     },
     "content---blog-0-b-4-09e": Object {
-      "loader": "() => import(/* webpackChunkName: 'content---blog-0-b-4-09e' */ \\"blog/2018-12-14-Happy-First-Birthday-Slash.md?truncated=true\\")",
+      "loader": "() => import(/* webpackChunkName: 'content---blog-0-b-4-09e' */ 'blog/2018-12-14-Happy-First-Birthday-Slash.md?truncated=true')",
       "modulePath": "blog/2018-12-14-Happy-First-Birthday-Slash.md?truncated=true",
     },
     "content---blog-7-b-8-fd9": Object {
-      "loader": "() => import(/* webpackChunkName: 'content---blog-7-b-8-fd9' */ \\"blog/2018-12-14-Happy-First-Birthday-Slash.md\\")",
+      "loader": "() => import(/* webpackChunkName: 'content---blog-7-b-8-fd9' */ 'blog/2018-12-14-Happy-First-Birthday-Slash.md')",
       "modulePath": "blog/2018-12-14-Happy-First-Birthday-Slash.md",
     },
     "metadata---blog-0-b-6-74c": Object {
-      "loader": "() => import(/* webpackChunkName: 'metadata---blog-0-b-6-74c' */ \\"blog-2018-12-14-happy-first-birthday-slash-d2c.json\\")",
+      "loader": "() => import(/* webpackChunkName: 'metadata---blog-0-b-6-74c' */ 'blog-2018-12-14-happy-first-birthday-slash-d2c.json')",
       "modulePath": "blog-2018-12-14-happy-first-birthday-slash-d2c.json",
     },
   },
@@ -62,31 +62,31 @@ exports[`loadRoutes nested route config 1`] = `
 Object {
   "registry": Object {
     "component---theme-doc-item-178-a40": Object {
-      "loader": "() => import(/* webpackChunkName: 'component---theme-doc-item-178-a40' */ \\"@theme/DocItem\\")",
+      "loader": "() => import(/* webpackChunkName: 'component---theme-doc-item-178-a40' */ '@theme/DocItem')",
       "modulePath": "@theme/DocItem",
     },
     "component---theme-doc-page-1-be-9be": Object {
-      "loader": "() => import(/* webpackChunkName: 'component---theme-doc-page-1-be-9be' */ \\"@theme/DocPage\\")",
+      "loader": "() => import(/* webpackChunkName: 'component---theme-doc-page-1-be-9be' */ '@theme/DocPage')",
       "modulePath": "@theme/DocPage",
     },
     "content---docs-foo-baz-8-ce-61e": Object {
-      "loader": "() => import(/* webpackChunkName: 'content---docs-foo-baz-8-ce-61e' */ \\"docs/foo/baz.md\\")",
+      "loader": "() => import(/* webpackChunkName: 'content---docs-foo-baz-8-ce-61e' */ 'docs/foo/baz.md')",
       "modulePath": "docs/foo/baz.md",
     },
     "content---docs-helloaff-811": Object {
-      "loader": "() => import(/* webpackChunkName: 'content---docs-helloaff-811' */ \\"docs/hello.md\\")",
+      "loader": "() => import(/* webpackChunkName: 'content---docs-helloaff-811' */ 'docs/hello.md')",
       "modulePath": "docs/hello.md",
     },
     "docsMetadata---docs-routef-34-881": Object {
-      "loader": "() => import(/* webpackChunkName: 'docsMetadata---docs-routef-34-881' */ \\"docs-b5f.json\\")",
+      "loader": "() => import(/* webpackChunkName: 'docsMetadata---docs-routef-34-881' */ 'docs-b5f.json')",
       "modulePath": "docs-b5f.json",
     },
     "metadata---docs-foo-baz-2-cf-fa7": Object {
-      "loader": "() => import(/* webpackChunkName: 'metadata---docs-foo-baz-2-cf-fa7' */ \\"docs-foo-baz-dd9.json\\")",
+      "loader": "() => import(/* webpackChunkName: 'metadata---docs-foo-baz-2-cf-fa7' */ 'docs-foo-baz-dd9.json')",
       "modulePath": "docs-foo-baz-dd9.json",
     },
     "metadata---docs-hello-956-741": Object {
-      "loader": "() => import(/* webpackChunkName: 'metadata---docs-hello-956-741' */ \\"docs-hello-da2.json\\")",
+      "loader": "() => import(/* webpackChunkName: 'metadata---docs-hello-956-741' */ 'docs-hello-da2.json')",
       "modulePath": "docs-hello-da2.json",
     },
   },
@@ -146,7 +146,7 @@ exports[`loadRoutes route config with empty (but valid) path string 1`] = `
 Object {
   "registry": Object {
     "component---hello-world-jse-0-f-b6c": Object {
-      "loader": "() => import(/* webpackChunkName: 'component---hello-world-jse-0-f-b6c' */ \\"hello/world.js\\")",
+      "loader": "() => import(/* webpackChunkName: 'component---hello-world-jse-0-f-b6c' */ 'hello/world.js')",
       "modulePath": "hello/world.js",
     },
   },
diff --git a/packages/docusaurus/src/server/index.ts b/packages/docusaurus/src/server/index.ts
index c8bca3ddd8..1c18f9a4b0 100644
--- a/packages/docusaurus/src/server/index.ts
+++ b/packages/docusaurus/src/server/index.ts
@@ -7,6 +7,7 @@
 
 import {
   generate,
+  escapePath,
   DEFAULT_BUILD_DIR_NAME,
   DEFAULT_CONFIG_FILE_NAME,
   GENERATED_FILES_DIR_NAME,
@@ -323,8 +324,7 @@ export async function load(
     `export default [\n${clientModules
       // import() is async so we use require() because client modules can have
       // CSS and the order matters for loading CSS.
-      // We need to JSON.stringify so that if its on windows, backslash are escaped.
-      .map((module) => `  require(${JSON.stringify(module)}),`)
+      .map((module) => `  require('${escapePath(module)}'),`)
       .join('\n')}\n];\n`,
   );
 
@@ -343,10 +343,9 @@ ${Object.keys(registry)
   .sort()
   .map(
     (key) =>
-      // We need to JSON.stringify so that if its on windows, backslash are escaped.
-      `  '${key}': [${registry[key].loader}, ${JSON.stringify(
+      `  '${key}': [${registry[key].loader}, '${escapePath(
         registry[key].modulePath,
-      )}, require.resolveWeak(${JSON.stringify(registry[key].modulePath)})],`,
+      )}', require.resolveWeak('${escapePath(registry[key].modulePath)}')],`,
   )
   .join('\n')}};\n`,
   );
diff --git a/packages/docusaurus/src/server/routes.ts b/packages/docusaurus/src/server/routes.ts
index 91740d8df1..ac6a505e14 100644
--- a/packages/docusaurus/src/server/routes.ts
+++ b/packages/docusaurus/src/server/routes.ts
@@ -10,6 +10,7 @@ import {
   normalizeUrl,
   removeSuffix,
   simpleHash,
+  escapePath,
 } from '@docusaurus/utils';
 import {has, isPlainObject, isString} from 'lodash';
 import {stringify} from 'querystring';
@@ -232,10 +233,9 @@ function genRouteChunkNames(
   if (isModule(value)) {
     const modulePath = getModulePath(value);
     const chunkName = genChunkName(modulePath, prefix, name);
-    // We need to JSON.stringify so that if its on windows, backslashes are escaped.
-    const loader = `() => import(/* webpackChunkName: '${chunkName}' */ ${JSON.stringify(
+    const loader = `() => import(/* webpackChunkName: '${chunkName}' */ '${escapePath(
       modulePath,
-    )})`;
+    )}')`;
 
     registry[chunkName] = {
       loader,