diff --git a/packages/tailwindcss-language-server/src/projects.ts b/packages/tailwindcss-language-server/src/projects.ts
index 5904ee91..6704c871 100644
--- a/packages/tailwindcss-language-server/src/projects.ts
+++ b/packages/tailwindcss-language-server/src/projects.ts
@@ -72,6 +72,7 @@ import {
   pathToFileURL,
   changeAffectsFile,
   normalizePath,
+  normalizeDriveLetter,
 } from './utils'
 import type { DocumentService } from './documents'
 import type { ProjectConfig } from './project-locator'
@@ -266,7 +267,7 @@ export async function createProjectService(
     let isPackageMatcher = picomatch(`**/${PACKAGE_LOCK_GLOB}`, { dot: true })
 
     for (let change of changes) {
-      let file = normalizePath(change.file)
+      let file = normalizeDriveLetter(normalizePath(change.file))
 
       let isConfigFile = changeAffectsFile(file, [projectConfig.configPath])
       let isDependency = changeAffectsFile(file, state.dependencies ?? [])
@@ -1552,7 +1553,7 @@ function getContentDocumentSelectorFromConfigFile(
         : path.resolve(contentBase, item),
     )
     .map((item) => ({
-      pattern: normalizePath(item),
+      pattern: normalizeDriveLetter(normalizePath(item)),
       priority: DocumentSelectorPriority.CONTENT_FILE,
     }))
 }
diff --git a/packages/tailwindcss-language-server/src/tw.ts b/packages/tailwindcss-language-server/src/tw.ts
index 6c660c2c..b073327b 100644
--- a/packages/tailwindcss-language-server/src/tw.ts
+++ b/packages/tailwindcss-language-server/src/tw.ts
@@ -77,7 +77,9 @@ async function getConfigFileFromCssFile(cssFile: string): Promise<string | null>
   if (!match) {
     return null
   }
-  return normalizePath(path.resolve(path.dirname(cssFile), match.groups.config.slice(1, -1)))
+  return normalizeDriveLetter(
+    normalizePath(path.resolve(path.dirname(cssFile), match.groups.config.slice(1, -1))),
+  )
 }
 
 export class TW {
@@ -191,7 +193,7 @@ export class TW {
 
     function getExplicitConfigFiles(settings: TailwindCssSettings) {
       function resolvePathForConfig(filepath: string) {
-        return normalizePath(path.resolve(userDefinedConfigBase, filepath))
+        return normalizeDriveLetter(normalizePath(path.resolve(userDefinedConfigBase, filepath)))
       }
 
       let configFileOrFiles = settings.experimental.configFile
@@ -334,7 +336,11 @@ export class TW {
 
         let isCssFile = isCssMatcher(`**/${CSS_GLOB}`)
         if (isCssFile && change.type !== FileChangeType.Deleted) {
-          let configPath = await getConfigFileFromCssFile(change.file)
+          // TODO: Determine if we can only use `normalizedFilename`
+          let configPath =
+            (await getConfigFileFromCssFile(normalizedFilename)) ||
+            (await getConfigFileFromCssFile(change.file))
+
           if (
             cssFileConfigMap.has(normalizedFilename) &&
             cssFileConfigMap.get(normalizedFilename) !== configPath
diff --git a/packages/tailwindcss-language-server/src/util/getModuleDependencies.ts b/packages/tailwindcss-language-server/src/util/getModuleDependencies.ts
index 8b700ee9..aee0119a 100644
--- a/packages/tailwindcss-language-server/src/util/getModuleDependencies.ts
+++ b/packages/tailwindcss-language-server/src/util/getModuleDependencies.ts
@@ -1,7 +1,7 @@
 // https://github.com/tailwindlabs/tailwindcss/blob/bac5ecf0040aa9a788d1b22d706506146ee831ff/src/lib/getModuleDependencies.js
 import fs from 'fs'
 import path from 'path'
-import { normalizePath } from '../utils'
+import { normalizeDriveLetter, normalizePath } from '../utils'
 
 let jsExtensions = ['.js', '.cjs', '.mjs']
 
@@ -83,5 +83,5 @@ export function getModuleDependencies(absoluteFilePath: string): string[] {
     _getModuleDependencies(absoluteFilePath, path.dirname(absoluteFilePath), new Set()),
   )
     .filter((file) => file !== absoluteFilePath)
-    .map((file) => normalizePath(file))
+    .map((file) => normalizeDriveLetter(normalizePath(file)))
 }