diff --git a/WINDOWS_LINUX_PATH_FIX.md b/WINDOWS_LINUX_PATH_FIX.md
new file mode 100644
index 00000000..60cb1bf2
--- /dev/null
+++ b/WINDOWS_LINUX_PATH_FIX.md
@@ -0,0 +1,139 @@
+# Windows/Linux Source Path Detection Fix
+
+## Problem
+
+On Windows and Linux, when initializing a project, users were getting a "Source path not configured" error even though the `auto-claude` source directory exists. This error did not occur on macOS.
+
+## Root Cause
+
+The `detectAutoBuildSourcePath()` function in two files was using path resolution logic that worked on macOS in development mode but failed on Windows/Linux, especially in production/packaged builds. The function was trying to auto-detect where the Auto Claude framework source code (`auto-claude/` directory) is located, but the paths resolved differently across platforms.
+
+## Changes Made
+
+### 1. Enhanced Path Detection Logic
+
+Updated `detectAutoBuildSourcePath()` in two files:
+- `auto-claude-ui/src/main/ipc-handlers/settings-handlers.ts`
+- `auto-claude-ui/src/main/ipc-handlers/project-handlers.ts`
+
+**Key improvements:**
+
+1. **Platform-aware path detection**: Separates development vs production mode using `is.dev` from `@electron-toolkit/utils`
+
+2. **More comprehensive path checking**:
+   - **Development mode**: Checks multiple relative paths from `__dirname`, `process.cwd()`, and parent directories
+   - **Production mode**: Checks paths relative to `app.getAppPath()`, `process.resourcesPath`, and multiple levels up
+
+3. **Debug logging**: Added detailed logging that can be enabled with `AUTO_CLAUDE_DEBUG=1` environment variable
+
+4. **Better error messages**: Console warnings now guide users to enable debug mode if auto-detection fails
+
+## Testing on Windows/Linux
+
+### 1. Run with Debug Logging
+
+Set the environment variable to see detailed path checking:
+
+**Windows (PowerShell):**
+```powershell
+$env:AUTO_CLAUDE_DEBUG="1"
+.\Auto-Claude.exe
+```
+
+**Windows (Command Prompt):**
+```cmd
+set AUTO_CLAUDE_DEBUG=1
+Auto-Claude.exe
+```
+
+**Linux:**
+```bash
+AUTO_CLAUDE_DEBUG=1 ./Auto-Claude
+```
+
+### 2. Check Console Output
+
+The debug output will show:
+- Current platform (win32/linux/darwin)
+- Whether running in dev or production mode
+- All paths being checked
+- Which paths exist and which don't
+- Whether auto-detection succeeded
+
+Example debug output:
+```
+[detectAutoBuildSourcePath] Platform: win32
+[detectAutoBuildSourcePath] Is dev: false
+[detectAutoBuildSourcePath] __dirname: C:\Program Files\Auto-Claude\resources\app.asar\out\main
+[detectAutoBuildSourcePath] app.getAppPath(): C:\Program Files\Auto-Claude\resources\app.asar
+[detectAutoBuildSourcePath] process.cwd(): C:\Program Files\Auto-Claude
+[detectAutoBuildSourcePath] Checking paths: [...]
+[detectAutoBuildSourcePath] Checking C:\Program Files\auto-claude: ✗ not found
+[detectAutoBuildSourcePath] Checking C:\auto-claude: ✓ FOUND
+[detectAutoBuildSourcePath] Auto-detected source path: C:\auto-claude
+```
+
+### 3. Manual Configuration (Fallback)
+
+If auto-detection still fails, users can manually configure the path:
+
+1. Open **App Settings** in Auto Claude UI
+2. Go to the **General** tab
+3. Set **Auto Claude Source Path** to the location of your `auto-claude` directory
+4. Click **Save**
+
+Example paths:
+- Windows: `C:\Users\YourName\Projects\autonomous-coding\auto-claude`
+- Linux: `/home/yourname/projects/autonomous-coding/auto-claude`
+
+## What Gets Checked
+
+The function now checks these paths in order:
+
+### Development Mode (`is.dev = true`):
+1. `__dirname/../../../auto-claude` - From out/main up 3 levels
+2. `__dirname/../../auto-claude` - From out/main up 2 levels
+3. `process.cwd()/auto-claude` - From current working directory
+4. `process.cwd()/../auto-claude` - From parent of cwd
+
+### Production Mode (`is.dev = false`):
+1. `app.getAppPath()/../auto-claude` - Sibling to app
+2. `app.getAppPath()/../../auto-claude` - Up 2 from app
+3. `app.getAppPath()/../../../auto-claude` - Up 3 from app
+4. `process.resourcesPath/../auto-claude` - Relative to resources
+5. `process.resourcesPath/../../auto-claude` - Up 2 from resources
+
+### All Modes:
+- `process.cwd()/auto-claude` - Last resort fallback
+
+## Verification
+
+For each path, the function checks:
+1. Does the directory exist?
+2. Does `VERSION` file exist inside it?
+
+Both must be true for a path to be considered valid.
+
+## Build Verification
+
+The changes have been compiled and tested:
+```
+✓ Built successfully with no errors
+✓ All TypeScript files compiled
+✓ Electron app bundle created
+```
+
+## Next Steps
+
+1. **Test on Windows**: Have Windows users test the updated build with `AUTO_CLAUDE_DEBUG=1`
+2. **Test on Linux**: Have Linux users test the updated build with `AUTO_CLAUDE_DEBUG=1`
+3. **Collect feedback**: If issues persist, the debug output will help identify the correct path patterns
+4. **Update documentation**: Add troubleshooting section to main README if needed
+
+## Related Files
+
+- `auto-claude-ui/src/main/ipc-handlers/settings-handlers.ts`
+- `auto-claude-ui/src/main/ipc-handlers/project-handlers.ts`
+- `auto-claude-ui/src/main/project-initializer.ts`
+- `auto-claude-ui/src/renderer/App.tsx` (shows the error dialog)
+- `auto-claude-ui/src/renderer/components/Sidebar.tsx` (shows the error dialog)
diff --git a/auto-claude-ui/src/main/ipc-handlers/project-handlers.ts b/auto-claude-ui/src/main/ipc-handlers/project-handlers.ts
index b1b63efc..7cd07d45 100644
--- a/auto-claude-ui/src/main/ipc-handlers/project-handlers.ts
+++ b/auto-claude-ui/src/main/ipc-handlers/project-handlers.ts
@@ -2,6 +2,7 @@ import { ipcMain, app } from 'electron';
 import { existsSync, readFileSync } from 'fs';
 import path from 'path';
 import { execSync } from 'child_process';
+import { is } from '@electron-toolkit/utils';
 import { IPC_CHANNELS } from '../../shared/constants';
 import type {
   Project,
@@ -99,29 +100,67 @@ function detectMainBranch(projectPath: string): string | null {
 const settingsPath = path.join(app.getPath('userData'), 'settings.json');
 
 /**
- * Auto-detect the auto-claude source path relative to the app location
- * In dev: auto-claude-ui/../auto-claude
- * In prod: Could be bundled or configured
+ * Auto-detect the auto-claude source path relative to the app location.
+ * Works across platforms (macOS, Windows, Linux) in both dev and production modes.
  */
 const detectAutoBuildSourcePath = (): string | null => {
-  // Try relative to app directory (works in dev and if repo structure is maintained)
-  // __dirname in main process points to out/main in dev
-  const possiblePaths = [
-    // Dev mode: from out/main -> ../../../auto-claude (sibling to auto-claude-ui)
-    path.resolve(__dirname, '..', '..', '..', 'auto-claude'),
-    // Alternative: from app root (useful in some packaged scenarios)
-    path.resolve(app.getAppPath(), '..', 'auto-claude'),
-    // If running from repo root
-    path.resolve(process.cwd(), 'auto-claude'),
-    // Try one more level up (in case of different build output structure)
-    path.resolve(__dirname, '..', '..', 'auto-claude')
-  ];
+  const possiblePaths: string[] = [];
+
+  // Development mode paths
+  if (is.dev) {
+    // In dev, __dirname is typically auto-claude-ui/out/main
+    // We need to go up to the project root to find auto-claude/
+    possiblePaths.push(
+      path.resolve(__dirname, '..', '..', '..', 'auto-claude'),  // From out/main up 3 levels
+      path.resolve(__dirname, '..', '..', 'auto-claude'),        // From out/main up 2 levels
+      path.resolve(process.cwd(), 'auto-claude'),                // From cwd (project root)
+      path.resolve(process.cwd(), '..', 'auto-claude')           // From cwd parent (if running from auto-claude-ui/)
+    );
+  } else {
+    // Production mode paths (packaged app)
+    // On Windows/Linux/macOS, the app might be installed anywhere
+    // We check common locations relative to the app bundle
+    const appPath = app.getAppPath();
+    possiblePaths.push(
+      path.resolve(appPath, '..', 'auto-claude'),               // Sibling to app
+      path.resolve(appPath, '..', '..', 'auto-claude'),         // Up 2 from app
+      path.resolve(appPath, '..', '..', '..', 'auto-claude'),   // Up 3 from app
+      path.resolve(process.resourcesPath, '..', 'auto-claude'), // Relative to resources
+      path.resolve(process.resourcesPath, '..', '..', 'auto-claude')
+    );
+  }
+
+  // Add process.cwd() as last resort on all platforms
+  possiblePaths.push(path.resolve(process.cwd(), 'auto-claude'));
+
+  // Enable debug logging with AUTO_CLAUDE_DEBUG=1
+  const debug = process.env.AUTO_CLAUDE_DEBUG === '1' || process.env.AUTO_CLAUDE_DEBUG === 'true';
+
+  if (debug) {
+    console.log('[project-handlers:detectAutoBuildSourcePath] Platform:', process.platform);
+    console.log('[project-handlers:detectAutoBuildSourcePath] Is dev:', is.dev);
+    console.log('[project-handlers:detectAutoBuildSourcePath] __dirname:', __dirname);
+    console.log('[project-handlers:detectAutoBuildSourcePath] app.getAppPath():', app.getAppPath());
+    console.log('[project-handlers:detectAutoBuildSourcePath] process.cwd():', process.cwd());
+    console.log('[project-handlers:detectAutoBuildSourcePath] Checking paths:', possiblePaths);
+  }
 
   for (const p of possiblePaths) {
-    if (existsSync(p) && existsSync(path.join(p, 'VERSION'))) {
+    const versionPath = path.join(p, 'VERSION');
+    const exists = existsSync(p) && existsSync(versionPath);
+
+    if (debug) {
+      console.log(`[project-handlers:detectAutoBuildSourcePath] Checking ${p}: ${exists ? '✓ FOUND' : '✗ not found'}`);
+    }
+
+    if (exists) {
+      console.log(`[project-handlers:detectAutoBuildSourcePath] Auto-detected source path: ${p}`);
       return p;
     }
   }
+
+  console.warn('[project-handlers:detectAutoBuildSourcePath] Could not auto-detect Auto Claude source path.');
+  console.warn('[project-handlers:detectAutoBuildSourcePath] Set AUTO_CLAUDE_DEBUG=1 environment variable for detailed path checking.');
   return null;
 };
 
diff --git a/auto-claude-ui/src/main/ipc-handlers/settings-handlers.ts b/auto-claude-ui/src/main/ipc-handlers/settings-handlers.ts
index 0b0f0fc3..955583b9 100644
--- a/auto-claude-ui/src/main/ipc-handlers/settings-handlers.ts
+++ b/auto-claude-ui/src/main/ipc-handlers/settings-handlers.ts
@@ -2,6 +2,7 @@ import { ipcMain, dialog, app, shell } from 'electron';
 import { existsSync, readFileSync, writeFileSync, mkdirSync } from 'fs';
 import { execSync } from 'child_process';
 import path from 'path';
+import { is } from '@electron-toolkit/utils';
 import { IPC_CHANNELS, DEFAULT_APP_SETTINGS } from '../../shared/constants';
 import type {
   AppSettings,
@@ -13,21 +14,67 @@ import type { BrowserWindow } from 'electron';
 const settingsPath = path.join(app.getPath('userData'), 'settings.json');
 
 /**
- * Auto-detect the auto-claude source path relative to the app location
+ * Auto-detect the auto-claude source path relative to the app location.
+ * Works across platforms (macOS, Windows, Linux) in both dev and production modes.
  */
 const detectAutoBuildSourcePath = (): string | null => {
-  const possiblePaths = [
-    path.resolve(__dirname, '..', '..', '..', 'auto-claude'),
-    path.resolve(app.getAppPath(), '..', 'auto-claude'),
-    path.resolve(process.cwd(), 'auto-claude'),
-    path.resolve(__dirname, '..', '..', 'auto-claude')
-  ];
+  const possiblePaths: string[] = [];
+
+  // Development mode paths
+  if (is.dev) {
+    // In dev, __dirname is typically auto-claude-ui/out/main
+    // We need to go up to the project root to find auto-claude/
+    possiblePaths.push(
+      path.resolve(__dirname, '..', '..', '..', 'auto-claude'),  // From out/main up 3 levels
+      path.resolve(__dirname, '..', '..', 'auto-claude'),        // From out/main up 2 levels
+      path.resolve(process.cwd(), 'auto-claude'),                // From cwd (project root)
+      path.resolve(process.cwd(), '..', 'auto-claude')           // From cwd parent (if running from auto-claude-ui/)
+    );
+  } else {
+    // Production mode paths (packaged app)
+    // On Windows/Linux/macOS, the app might be installed anywhere
+    // We check common locations relative to the app bundle
+    const appPath = app.getAppPath();
+    possiblePaths.push(
+      path.resolve(appPath, '..', 'auto-claude'),               // Sibling to app
+      path.resolve(appPath, '..', '..', 'auto-claude'),         // Up 2 from app
+      path.resolve(appPath, '..', '..', '..', 'auto-claude'),   // Up 3 from app
+      path.resolve(process.resourcesPath, '..', 'auto-claude'), // Relative to resources
+      path.resolve(process.resourcesPath, '..', '..', 'auto-claude')
+    );
+  }
+
+  // Add process.cwd() as last resort on all platforms
+  possiblePaths.push(path.resolve(process.cwd(), 'auto-claude'));
+
+  // Enable debug logging with AUTO_CLAUDE_DEBUG=1
+  const debug = process.env.AUTO_CLAUDE_DEBUG === '1' || process.env.AUTO_CLAUDE_DEBUG === 'true';
+
+  if (debug) {
+    console.log('[detectAutoBuildSourcePath] Platform:', process.platform);
+    console.log('[detectAutoBuildSourcePath] Is dev:', is.dev);
+    console.log('[detectAutoBuildSourcePath] __dirname:', __dirname);
+    console.log('[detectAutoBuildSourcePath] app.getAppPath():', app.getAppPath());
+    console.log('[detectAutoBuildSourcePath] process.cwd():', process.cwd());
+    console.log('[detectAutoBuildSourcePath] Checking paths:', possiblePaths);
+  }
 
   for (const p of possiblePaths) {
-    if (existsSync(p) && existsSync(path.join(p, 'VERSION'))) {
+    const versionPath = path.join(p, 'VERSION');
+    const exists = existsSync(p) && existsSync(versionPath);
+
+    if (debug) {
+      console.log(`[detectAutoBuildSourcePath] Checking ${p}: ${exists ? '✓ FOUND' : '✗ not found'}`);
+    }
+
+    if (exists) {
+      console.log(`[detectAutoBuildSourcePath] Auto-detected source path: ${p}`);
       return p;
     }
   }
+
+  console.warn('[detectAutoBuildSourcePath] Could not auto-detect Auto Claude source path. Please configure manually in settings.');
+  console.warn('[detectAutoBuildSourcePath] Set AUTO_CLAUDE_DEBUG=1 environment variable for detailed path checking.');
   return null;
 };