diff --git a/.changeset/dull-jokes-buy.md b/.changeset/dull-jokes-buy.md
new file mode 100644
index 0000000000..2230b85f0b
--- /dev/null
+++ b/.changeset/dull-jokes-buy.md
@@ -0,0 +1,5 @@
+---
+"@lynx-js/react-rsbuild-plugin": patch
+---
+
+fix(rspeedy/plugin-react): mkdir main:background fails in windows
diff --git a/packages/rspeedy/plugin-react/src/entry.ts b/packages/rspeedy/plugin-react/src/entry.ts
index a07dce0a61..4952e2498d 100644
--- a/packages/rspeedy/plugin-react/src/entry.ts
+++ b/packages/rspeedy/plugin-react/src/entry.ts
@@ -78,6 +78,10 @@ export function applyEntry(
           : config.output?.filename
       ) ?? '[name].[platform].bundle'
 
+      // We do not use `${entryName}__background` since the default CSS name is `[name]/[name].css`.
+      // We would like to avoid adding `__background` to the output CSS filename.
+      const mainThreadEntry = `${entryName}__main-thread`
+
       const mainThreadName = path.join(
         isLynx
           // TODO: config intermediate
@@ -85,11 +89,8 @@ export function applyEntry(
           // For non-Lynx environment, the entry is not deleted.
           // So we do not put it in the intermediate.
           : '',
-        `${entryName}/main-thread.js`,
+        `${mainThreadEntry}/main-thread.js`,
       )
-      // We do not use `${entryName}:main-thread` since the default CSS name is `[name]/[name].css`.
-      // We would like to avoid adding `:main-thread` to the output CSS filename.
-      const mainThreadEntry = entryName
 
       const backgroundName = path.join(
         isLynx
@@ -100,7 +101,7 @@ export function applyEntry(
           : '',
         getBackgroundFilename(entryName, environment.config, isProd),
       )
-      const backgroundEntry = `${entryName}:background`
+      const backgroundEntry = entryName
 
       mainThreadChunks.push(mainThreadName)
 
diff --git a/packages/rspeedy/plugin-react/src/splitChunks.ts b/packages/rspeedy/plugin-react/src/splitChunks.ts
index af077acf0d..c04548c315 100644
--- a/packages/rspeedy/plugin-react/src/splitChunks.ts
+++ b/packages/rspeedy/plugin-react/src/splitChunks.ts
@@ -93,7 +93,7 @@ export const applySplitChunksRule = (
     rspackConfig.optimization.splitChunks.chunks = function chunks(chunk) {
       // TODO: support `splitChunks.chunks: 'async'`
       // We don't want main thread to be splitted
-      return Boolean(chunk.name?.includes(':background'))
+      return !chunk.name?.includes('__main-thread')
     }
     return rspackConfig
   })
diff --git a/packages/rspeedy/plugin-react/test/config.test.ts b/packages/rspeedy/plugin-react/test/config.test.ts
index 10929b1a44..413ecb80fa 100644
--- a/packages/rspeedy/plugin-react/test/config.test.ts
+++ b/packages/rspeedy/plugin-react/test/config.test.ts
@@ -440,18 +440,18 @@ describe('Config', () => {
       expect(config?.entry).toMatchInlineSnapshot(`
         {
           "main": {
-            "filename": ".rspeedy/main/main-thread.js",
+            "filename": ".rspeedy/main/background.[contenthash:8].js",
             "import": [
               "./fixtures/basic.tsx",
             ],
-            "layer": "react:main-thread",
+            "layer": "react:background",
           },
-          "main:background": {
-            "filename": ".rspeedy/main/background.[contenthash:8].js",
+          "main__main-thread": {
+            "filename": ".rspeedy/main__main-thread/main-thread.js",
             "import": [
               "./fixtures/basic.tsx",
             ],
-            "layer": "react:background",
+            "layer": "react:main-thread",
           },
         }
       `)
@@ -484,33 +484,33 @@ describe('Config', () => {
       expect(config?.entry).toMatchInlineSnapshot(`
         {
           "bar": {
-            "filename": ".rspeedy/bar/main-thread.js",
-            "import": [
-              "./fixtures/basic.tsx",
-            ],
-            "layer": "react:main-thread",
-          },
-          "bar:background": {
             "filename": ".rspeedy/bar/background.[contenthash:8].js",
             "import": [
               "./fixtures/basic.tsx",
             ],
             "layer": "react:background",
           },
-          "foo": {
-            "filename": ".rspeedy/foo/main-thread.js",
+          "bar__main-thread": {
+            "filename": ".rspeedy/bar__main-thread/main-thread.js",
             "import": [
               "./fixtures/basic.tsx",
             ],
             "layer": "react:main-thread",
           },
-          "foo:background": {
+          "foo": {
             "filename": ".rspeedy/foo/background.[contenthash:8].js",
             "import": [
               "./fixtures/basic.tsx",
             ],
             "layer": "react:background",
           },
+          "foo__main-thread": {
+            "filename": ".rspeedy/foo__main-thread/main-thread.js",
+            "import": [
+              "./fixtures/basic.tsx",
+            ],
+            "layer": "react:main-thread",
+          },
         }
       `)
     })
@@ -542,33 +542,33 @@ describe('Config', () => {
       expect(config?.entry).toMatchInlineSnapshot(`
         {
           "foo/bar": {
-            "filename": ".rspeedy/foo/bar/main-thread.js",
-            "import": [
-              "./fixtures/basic.tsx",
-            ],
-            "layer": "react:main-thread",
-          },
-          "foo/bar:background": {
             "filename": ".rspeedy/foo/bar/background.[contenthash:8].js",
             "import": [
               "./fixtures/basic.tsx",
             ],
             "layer": "react:background",
           },
-          "foo/baz": {
-            "filename": ".rspeedy/foo/baz/main-thread.js",
+          "foo/bar__main-thread": {
+            "filename": ".rspeedy/foo/bar__main-thread/main-thread.js",
             "import": [
               "./fixtures/basic.tsx",
             ],
             "layer": "react:main-thread",
           },
-          "foo/baz:background": {
+          "foo/baz": {
             "filename": ".rspeedy/foo/baz/background.[contenthash:8].js",
             "import": [
               "./fixtures/basic.tsx",
             ],
             "layer": "react:background",
           },
+          "foo/baz__main-thread": {
+            "filename": ".rspeedy/foo/baz__main-thread/main-thread.js",
+            "import": [
+              "./fixtures/basic.tsx",
+            ],
+            "layer": "react:main-thread",
+          },
         }
       `)
     })
@@ -606,46 +606,46 @@ describe('Config', () => {
       expect(config?.entry).toMatchInlineSnapshot(`
         {
           "bar": {
-            "filename": ".rspeedy/bar/main-thread.js",
+            "filename": ".rspeedy/bar/background.js",
             "import": [
               "./fixtures/basic.tsx",
             ],
-            "layer": "react:main-thread",
+            "layer": "react:background",
           },
-          "bar:background": {
-            "filename": ".rspeedy/bar/background.js",
+          "bar__main-thread": {
+            "filename": ".rspeedy/bar__main-thread/main-thread.js",
             "import": [
               "./fixtures/basic.tsx",
             ],
-            "layer": "react:background",
+            "layer": "react:main-thread",
           },
           "foo": {
-            "filename": ".rspeedy/foo/main-thread.js",
+            "filename": ".rspeedy/foo/background.js",
             "import": [
               "./fixtures/basic.tsx",
             ],
-            "layer": "react:main-thread",
+            "layer": "react:background",
           },
           "foo/baz": {
-            "filename": ".rspeedy/foo/baz/main-thread.js",
+            "filename": ".rspeedy/foo/baz/background.js",
             "import": [
               "./fixtures/basic.tsx",
             ],
-            "layer": "react:main-thread",
+            "layer": "react:background",
           },
-          "foo/baz:background": {
-            "filename": ".rspeedy/foo/baz/background.js",
+          "foo/baz__main-thread": {
+            "filename": ".rspeedy/foo/baz__main-thread/main-thread.js",
             "import": [
               "./fixtures/basic.tsx",
             ],
-            "layer": "react:background",
+            "layer": "react:main-thread",
           },
-          "foo:background": {
-            "filename": ".rspeedy/foo/background.js",
+          "foo__main-thread": {
+            "filename": ".rspeedy/foo__main-thread/main-thread.js",
             "import": [
               "./fixtures/basic.tsx",
             ],
-            "layer": "react:background",
+            "layer": "react:main-thread",
           },
         }
       `)
@@ -682,18 +682,18 @@ describe('Config', () => {
       expect(config?.entry).toMatchInlineSnapshot(`
         {
           "main": {
-            "filename": ".rspeedy/main/main-thread.js",
+            "filename": ".rspeedy/main/main/background.js",
             "import": [
               "./fixtures/basic.tsx",
             ],
-            "layer": "react:main-thread",
+            "layer": "react:background",
           },
-          "main:background": {
-            "filename": ".rspeedy/main/main/background.js",
+          "main__main-thread": {
+            "filename": ".rspeedy/main__main-thread/main-thread.js",
             "import": [
               "./fixtures/basic.tsx",
             ],
-            "layer": "react:background",
+            "layer": "react:main-thread",
           },
         }
       `)
@@ -733,46 +733,46 @@ describe('Config', () => {
       expect(config?.entry).toMatchInlineSnapshot(`
         {
           "bar": {
-            "filename": ".rspeedy/bar/main-thread.js",
+            "filename": ".rspeedy/bar/background.js",
             "import": [
               "./fixtures/basic.tsx",
             ],
-            "layer": "react:main-thread",
+            "layer": "react:background",
           },
-          "bar:background": {
-            "filename": ".rspeedy/bar/background.js",
+          "bar__main-thread": {
+            "filename": ".rspeedy/bar__main-thread/main-thread.js",
             "import": [
               "./fixtures/basic.tsx",
             ],
-            "layer": "react:background",
+            "layer": "react:main-thread",
           },
           "foo": {
-            "filename": ".rspeedy/foo/main-thread.js",
+            "filename": ".rspeedy/foo/background.js",
             "import": [
               "./fixtures/basic.tsx",
             ],
-            "layer": "react:main-thread",
+            "layer": "react:background",
           },
           "foo/baz": {
-            "filename": ".rspeedy/foo/baz/main-thread.js",
+            "filename": ".rspeedy/foo/baz/background.js",
             "import": [
               "./fixtures/basic.tsx",
             ],
-            "layer": "react:main-thread",
+            "layer": "react:background",
           },
-          "foo/baz:background": {
-            "filename": ".rspeedy/foo/baz/background.js",
+          "foo/baz__main-thread": {
+            "filename": ".rspeedy/foo/baz__main-thread/main-thread.js",
             "import": [
               "./fixtures/basic.tsx",
             ],
-            "layer": "react:background",
+            "layer": "react:main-thread",
           },
-          "foo:background": {
-            "filename": ".rspeedy/foo/background.js",
+          "foo__main-thread": {
+            "filename": ".rspeedy/foo__main-thread/main-thread.js",
             "import": [
               "./fixtures/basic.tsx",
             ],
-            "layer": "react:background",
+            "layer": "react:main-thread",
           },
         }
       `)
@@ -807,18 +807,18 @@ describe('Config', () => {
       expect(config?.entry).toMatchInlineSnapshot(`
         {
           "main": {
-            "filename": ".rspeedy/main/main-thread.js",
+            "filename": ".rspeedy/main/background.js",
             "import": [
               "./fixtures/basic.tsx",
             ],
-            "layer": "react:main-thread",
+            "layer": "react:background",
           },
-          "main:background": {
-            "filename": ".rspeedy/main/background.js",
+          "main__main-thread": {
+            "filename": ".rspeedy/main__main-thread/main-thread.js",
             "import": [
               "./fixtures/basic.tsx",
             ],
-            "layer": "react:background",
+            "layer": "react:main-thread",
           },
         }
       `)
@@ -854,18 +854,18 @@ describe('Config', () => {
       expect(config?.entry).toMatchInlineSnapshot(`
         {
           "main": {
-            "filename": ".rspeedy/main/main-thread.js",
+            "filename": ".rspeedy/main/background.js",
             "import": [
               "./fixtures/basic.tsx",
             ],
-            "layer": "react:main-thread",
+            "layer": "react:background",
           },
-          "main:background": {
-            "filename": ".rspeedy/main/background.js",
+          "main__main-thread": {
+            "filename": ".rspeedy/main__main-thread/main-thread.js",
             "import": [
               "./fixtures/basic.tsx",
             ],
-            "layer": "react:background",
+            "layer": "react:main-thread",
           },
         }
       `)
@@ -900,18 +900,18 @@ describe('Config', () => {
       expect(config?.entry).toMatchInlineSnapshot(`
         {
           "main": {
-            "filename": ".rspeedy/main/main-thread.js",
+            "filename": ".rspeedy/main/background.[contenthash].js",
             "import": [
               "./fixtures/basic.tsx",
             ],
-            "layer": "react:main-thread",
+            "layer": "react:background",
           },
-          "main:background": {
-            "filename": ".rspeedy/main/background.[contenthash].js",
+          "main__main-thread": {
+            "filename": ".rspeedy/main__main-thread/main-thread.js",
             "import": [
               "./fixtures/basic.tsx",
             ],
-            "layer": "react:background",
+            "layer": "react:main-thread",
           },
         }
       `)
@@ -946,18 +946,18 @@ describe('Config', () => {
       expect(config?.entry).toMatchInlineSnapshot(`
         {
           "main": {
-            "filename": ".rspeedy/main/main-thread.js",
+            "filename": ".rspeedy/main/background.js",
             "import": [
               "./fixtures/basic.tsx",
             ],
-            "layer": "react:main-thread",
+            "layer": "react:background",
           },
-          "main:background": {
-            "filename": ".rspeedy/main/background.js",
+          "main__main-thread": {
+            "filename": ".rspeedy/main__main-thread/main-thread.js",
             "import": [
               "./fixtures/basic.tsx",
             ],
-            "layer": "react:background",
+            "layer": "react:main-thread",
           },
         }
       `)
@@ -989,14 +989,6 @@ describe('Config', () => {
       expect(config?.entry).toMatchInlineSnapshot(`
         {
           "main": {
-            "filename": ".rspeedy/main/main-thread.js",
-            "import": [
-              "./fixtures/basic.tsx",
-              "<WORKSPACE>/packages/webpack/css-extract-webpack-plugin/runtime/hotModuleReplacement.lepus.cjs",
-            ],
-            "layer": "react:main-thread",
-          },
-          "main:background": {
             "filename": ".rspeedy/main/background.js",
             "import": [
               "./fixtures/basic.tsx",
@@ -1006,6 +998,14 @@ describe('Config', () => {
             ],
             "layer": "react:background",
           },
+          "main__main-thread": {
+            "filename": ".rspeedy/main__main-thread/main-thread.js",
+            "import": [
+              "./fixtures/basic.tsx",
+              "<WORKSPACE>/packages/webpack/css-extract-webpack-plugin/runtime/hotModuleReplacement.lepus.cjs",
+            ],
+            "layer": "react:main-thread",
+          },
         }
       `)
     })
@@ -1039,14 +1039,6 @@ describe('Config', () => {
       expect(config?.entry).toMatchInlineSnapshot(`
         {
           "main": {
-            "filename": ".rspeedy/main/main-thread.js",
-            "import": [
-              "./fixtures/basic.tsx",
-              "<WORKSPACE>/packages/webpack/css-extract-webpack-plugin/runtime/hotModuleReplacement.lepus.cjs",
-            ],
-            "layer": "react:main-thread",
-          },
-          "main:background": {
             "filename": ".rspeedy/main/background.[contenthash].js",
             "import": [
               "./fixtures/basic.tsx",
@@ -1056,6 +1048,14 @@ describe('Config', () => {
             ],
             "layer": "react:background",
           },
+          "main__main-thread": {
+            "filename": ".rspeedy/main__main-thread/main-thread.js",
+            "import": [
+              "./fixtures/basic.tsx",
+              "<WORKSPACE>/packages/webpack/css-extract-webpack-plugin/runtime/hotModuleReplacement.lepus.cjs",
+            ],
+            "layer": "react:main-thread",
+          },
         }
       `)
     })
@@ -1440,8 +1440,8 @@ describe('Config', () => {
     expect(templatePlugin?.options).toMatchInlineSnapshot(`
       {
         "chunks": [
+          "main__main-thread",
           "main",
-          "main:background",
         ],
         "cssPlugins": [
           {
@@ -1593,12 +1593,12 @@ describe('MPA Config', () => {
     expect(templatePlugins.map(i => i.options.chunks)).toMatchInlineSnapshot(`
       [
         [
+          "foo__main-thread",
           "foo",
-          "foo:background",
         ],
         [
+          "bar__main-thread",
           "bar",
-          "bar:background",
         ],
       ]
     `)
@@ -1611,8 +1611,8 @@ describe('MPA Config', () => {
     // eslint-disable-next-line @typescript-eslint/no-unsafe-member-access
     expect(reactWebpackPlugin.options.mainThreadChunks).toMatchInlineSnapshot(`
       [
-        ".rspeedy/foo/main-thread.js",
-        ".rspeedy/bar/main-thread.js",
+        ".rspeedy/foo__main-thread/main-thread.js",
+        ".rspeedy/bar__main-thread/main-thread.js",
       ]
     `)
   })
@@ -1659,12 +1659,12 @@ describe('MPA Config', () => {
     expect(templatePlugins.map(i => i.options.chunks)).toMatchInlineSnapshot(`
       [
         [
+          "foo__main-thread",
           "foo",
-          "foo:background",
         ],
         [
+          "bar__main-thread",
           "bar",
-          "bar:background",
         ],
       ]
     `)
@@ -1677,8 +1677,8 @@ describe('MPA Config', () => {
     // eslint-disable-next-line @typescript-eslint/no-unsafe-member-access
     expect(reactWebpackPlugin.options.mainThreadChunks).toMatchInlineSnapshot(`
       [
-        ".rspeedy/foo/main-thread.js",
-        ".rspeedy/bar/main-thread.js",
+        ".rspeedy/foo__main-thread/main-thread.js",
+        ".rspeedy/bar__main-thread/main-thread.js",
       ]
     `)
   })
@@ -1720,8 +1720,8 @@ describe('MPA Config', () => {
     // eslint-disable-next-line @typescript-eslint/no-unsafe-member-access
     expect(reactWebpackPlugin.options.mainThreadChunks).toMatchInlineSnapshot(`
       [
-        "foo/main-thread.js",
-        "bar/main-thread.js",
+        "foo__main-thread/main-thread.js",
+        "bar__main-thread/main-thread.js",
       ]
     `)
   })
@@ -1768,12 +1768,12 @@ describe('MPA Config', () => {
     expect(templatePlugins.map(i => i.options.chunks)).toMatchInlineSnapshot(`
       [
         [
+          "foo__main-thread",
           "foo",
-          "foo:background",
         ],
         [
+          "bar__main-thread",
           "bar",
-          "bar:background",
         ],
       ]
     `)
@@ -1786,8 +1786,8 @@ describe('MPA Config', () => {
     // eslint-disable-next-line @typescript-eslint/no-unsafe-member-access
     expect(reactWebpackPlugin.options.mainThreadChunks).toMatchInlineSnapshot(`
       [
-        ".rspeedy/foo/main-thread.js",
-        ".rspeedy/bar/main-thread.js",
+        ".rspeedy/foo__main-thread/main-thread.js",
+        ".rspeedy/bar__main-thread/main-thread.js",
       ]
     `)
   })
@@ -1834,12 +1834,12 @@ describe('MPA Config', () => {
     expect(templatePlugins.map(i => i.options.chunks)).toMatchInlineSnapshot(`
       [
         [
+          "foo__main-thread",
           "foo",
-          "foo:background",
         ],
         [
+          "bar__main-thread",
           "bar",
-          "bar:background",
         ],
       ]
     `)
@@ -1852,8 +1852,8 @@ describe('MPA Config', () => {
     // eslint-disable-next-line @typescript-eslint/no-unsafe-member-access
     expect(reactWebpackPlugin.options.mainThreadChunks).toMatchInlineSnapshot(`
       [
-        ".rspeedy/foo/main-thread.js",
-        ".rspeedy/bar/main-thread.js",
+        ".rspeedy/foo__main-thread/main-thread.js",
+        ".rspeedy/bar__main-thread/main-thread.js",
       ]
     `)
   })
@@ -1901,12 +1901,12 @@ describe('MPA Config', () => {
     expect(templatePlugins.map(i => i.options.chunks)).toMatchInlineSnapshot(`
       [
         [
+          "foo__main-thread",
           "foo",
-          "foo:background",
         ],
         [
+          "bar__main-thread",
           "bar",
-          "bar:background",
         ],
       ]
     `)
@@ -1919,8 +1919,8 @@ describe('MPA Config', () => {
     // eslint-disable-next-line @typescript-eslint/no-unsafe-member-access
     expect(reactWebpackPlugin.options.mainThreadChunks).toMatchInlineSnapshot(`
       [
-        ".rspeedy/foo/main-thread.js",
-        ".rspeedy/bar/main-thread.js",
+        ".rspeedy/foo__main-thread/main-thread.js",
+        ".rspeedy/bar__main-thread/main-thread.js",
       ]
     `)
   })
@@ -1970,16 +1970,16 @@ describe('MPA Config', () => {
     expect(templatePlugins.map(i => i.options.chunks)).toMatchInlineSnapshot(`
       [
         [
+          "foo__main-thread",
           "foo",
-          "foo:background",
         ],
         [
+          "bar__main-thread",
           "bar",
-          "bar:background",
         ],
         [
+          "baz__main-thread",
           "baz",
-          "baz:background",
         ],
       ]
     `)
@@ -1992,9 +1992,9 @@ describe('MPA Config', () => {
     // eslint-disable-next-line @typescript-eslint/no-unsafe-member-access
     expect(reactWebpackPlugin.options.mainThreadChunks).toMatchInlineSnapshot(`
       [
-        ".rspeedy/foo/main-thread.js",
-        ".rspeedy/bar/main-thread.js",
-        ".rspeedy/baz/main-thread.js",
+        ".rspeedy/foo__main-thread/main-thread.js",
+        ".rspeedy/bar__main-thread/main-thread.js",
+        ".rspeedy/baz__main-thread/main-thread.js",
       ]
     `)
   })