diff --git a/client/src/extension.ts b/client/src/extension.ts
index 881b8bc..f27da30 100644
--- a/client/src/extension.ts
+++ b/client/src/extension.ts
@@ -1,12 +1,15 @@
 import * as path from 'path';
 import { getConfigLogLevel, Logger } from './logging';
-import { workspace, ExtensionContext } from 'vscode';
+import { workspace, ExtensionContext, window, commands } from 'vscode';
 import {
     LanguageClient,
     LanguageClientOptions,
     ServerOptions,
     TransportKind
 } from 'vscode-languageclient/node';
+import { existsSync } from 'fs';
+import { isAbsolute } from 'path';
+import { which } from './utils';
 
 
 export const SERVER_ID = 'cmakeIntelliSence';
@@ -14,15 +17,33 @@ export const SERVER_NAME = 'CMake Language Server';
 
 let client: LanguageClient;
 
-export function activate(context: ExtensionContext) {
+async function checkCMakePath(cmakePath: string) {
+    if (!existsSync(cmakePath)) {
+        if (which(cmakePath) === null) {
+            let select = await window.showErrorMessage(`Can not find cmakePath: ${cmakePath}`,
+                'Open Settings', 'Ignore');
+            if (select === 'Open Settings') {
+                commands.executeCommand('workbench.action.openSettings', 'cmakeIntelliSence.cmakePath');
+            }
+        }
+    }
+}
+
+export async function activate(context: ExtensionContext) {
     const config = workspace.getConfiguration(SERVER_ID);
     const logger = new Logger();
     logger.setLogLevel(getConfigLogLevel(config));
+    checkCMakePath(config.cmakePath);
 
     context.subscriptions.push(workspace.onDidChangeConfiguration((e) => {
         if (e.affectsConfiguration(`${SERVER_ID}.loggingLevel`)) {
             logger.setLogLevel(getConfigLogLevel(config));
         }
+
+        if (e.affectsConfiguration(`${SERVER_ID}.cmakePath`)) {
+            const cmakePath = workspace.getConfiguration(SERVER_ID).get<string>('cmakePath');
+            checkCMakePath(cmakePath);
+        }
     }));
 
     const serverModule = context.asAbsolutePath(
diff --git a/client/src/utils.ts b/client/src/utils.ts
new file mode 100644
index 0000000..7d39c60
--- /dev/null
+++ b/client/src/utils.ts
@@ -0,0 +1,26 @@
+import * as os from 'os';
+import * as path from 'path';
+import { existsSync } from 'fs';
+
+export function which(cmd: string): string {
+    let command: string;
+    let pathEnvSep: string;
+    if (os.type() === 'Windows_NT') {
+        if (!cmd.endsWith('.exe')) {
+            command = cmd + ".exe";
+        }
+        pathEnvSep = ';';
+    } else {
+        command = cmd;
+        pathEnvSep = ':';
+    }
+
+    for (const dir of process.env.PATH.split(pathEnvSep)) {
+        const absPath: string = dir + path.sep + command;
+        if (existsSync(absPath)) {
+            return absPath;
+        }
+    }
+
+    return null;
+}
\ No newline at end of file
diff --git a/server/src/utils.ts b/server/src/utils.ts
index 6aea714..0a7a0db 100644
--- a/server/src/utils.ts
+++ b/server/src/utils.ts
@@ -94,11 +94,13 @@ export function getIncludeFileUri(baseDir: URI, includeFileName: string): URI {
     return null;
 }
 
-function which(cmd: string): string {
+export function which(cmd: string): string {
     let command: string;
     let pathEnvSep: string;
     if (os.type() === 'Windows_NT') {
-        command = cmd + ".exe";
+        if (!cmd.endsWith('.exe')) {
+            command = cmd + ".exe";
+        }
         pathEnvSep = ';';
     } else {
         command = cmd;