diff --git a/package-lock.json b/package-lock.json
index 04a975a0..6d03f81f 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -50,7 +50,6 @@
         "resolve": "^1.20.0",
         "rollup-plugin-dts": "^3.0.2",
         "rollup-plugin-hashbang": "^2.2.2",
-        "slash": "^4.0.0",
         "string-argv": "^0.3.1",
         "strip-json-comments": "^3.1.1",
         "svelte": "3.37.0",
@@ -6048,18 +6047,6 @@
       "integrity": "sha512-bLGGlR1QxBcynn2d5YmDX4MGjlZvy2MRBDRNHLJ8VI6l6+9FUiyTFNJ0IveOSP0bcXgVDPRcfGqA0pjaqUpfVg==",
       "dev": true
     },
-    "node_modules/slash": {
-      "version": "4.0.0",
-      "resolved": "https://registry.npmjs.org/slash/-/slash-4.0.0.tgz",
-      "integrity": "sha512-3dOsAHXXUkQTpOYcoAxLIorMTp4gIQr5IW3iVb7A7lFIp0VHhnynm9izx6TssdrIcVIESAlVjtnO2K8bg+Coew==",
-      "dev": true,
-      "engines": {
-        "node": ">=12"
-      },
-      "funding": {
-        "url": "https://github.com/sponsors/sindresorhus"
-      }
-    },
     "node_modules/snapdragon": {
       "version": "0.8.2",
       "resolved": "https://registry.npmjs.org/snapdragon/-/snapdragon-0.8.2.tgz",
@@ -12032,12 +12019,6 @@
       "integrity": "sha512-bLGGlR1QxBcynn2d5YmDX4MGjlZvy2MRBDRNHLJ8VI6l6+9FUiyTFNJ0IveOSP0bcXgVDPRcfGqA0pjaqUpfVg==",
       "dev": true
     },
-    "slash": {
-      "version": "4.0.0",
-      "resolved": "https://registry.npmjs.org/slash/-/slash-4.0.0.tgz",
-      "integrity": "sha512-3dOsAHXXUkQTpOYcoAxLIorMTp4gIQr5IW3iVb7A7lFIp0VHhnynm9izx6TssdrIcVIESAlVjtnO2K8bg+Coew==",
-      "dev": true
-    },
     "snapdragon": {
       "version": "0.8.2",
       "resolved": "https://registry.npmjs.org/snapdragon/-/snapdragon-0.8.2.tgz",
diff --git a/package.json b/package.json
index cd28c7cc..e2c19ce8 100644
--- a/package.json
+++ b/package.json
@@ -62,7 +62,6 @@
     "resolve": "^1.20.0",
     "rollup-plugin-dts": "^3.0.2",
     "rollup-plugin-hashbang": "^2.2.2",
-    "slash": "^4.0.0",
     "string-argv": "^0.3.1",
     "strip-json-comments": "^3.1.1",
     "svelte": "3.37.0",
diff --git a/src/cli-main.ts b/src/cli-main.ts
index 73f9380a..ea0c8d41 100644
--- a/src/cli-main.ts
+++ b/src/cli-main.ts
@@ -2,8 +2,8 @@ import { readFileSync } from 'fs'
 import { join } from 'path'
 import { cac } from 'cac'
 import flat from 'flat'
-import slash from 'slash'
 import { Format, Options } from '.'
+import { slash } from './utils'
 
 function ensureArray(input: string): string[] {
   return Array.isArray(input) ? input : input.split(',')
diff --git a/src/index.ts b/src/index.ts
index 7733a944..25ee00a4 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -2,7 +2,7 @@ import path from 'path'
 import fs from 'fs'
 import { Worker } from 'worker_threads'
 import type { MarkRequired } from 'ts-essentials'
-import { removeFiles, debouncePromise } from './utils'
+import { removeFiles, debouncePromise, slash } from './utils'
 import { loadTsupConfig, resolveTsConfig } from './load'
 import glob from 'globby'
 import { handleError, PrettyError } from './errors'
@@ -242,6 +242,7 @@ export async function build(_options: Options) {
               ignored,
             })
             watcher.on('all', async (type, file) => {
+              file = slash(file)
               if (!buildDependencies.has(file)) return
 
               logger.info('CLI', `Change detected: ${type} ${file}`)
diff --git a/src/utils.ts b/src/utils.ts
index 703bc0fc..46b7bfa1 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -2,11 +2,6 @@ import fs from 'fs'
 import glob from 'globby'
 import resolveFrom from 'resolve-from'
 
-// No backslash in path
-function slash(input: string) {
-  return input.replace(/\\/g, '/')
-}
-
 export type External =
   | string
   | RegExp
@@ -108,3 +103,15 @@ export function debouncePromise<T extends unknown[]>(
     }
   }
 }
+
+// Taken from https://github.com/sindresorhus/slash/blob/main/index.js (MIT)
+export function slash(path: string) {
+  const isExtendedLengthPath = /^\\\\\?\\/.test(path)
+  const hasNonAscii = /[^\u0000-\u0080]+/.test(path)
+
+  if (isExtendedLengthPath || hasNonAscii) {
+    return path
+  }
+
+  return path.replace(/\\/g, '/')
+}