diff --git a/bun.lock b/bun.lock
index 29a4d4a..4b78ff3 100644
--- a/bun.lock
+++ b/bun.lock
@@ -4,6 +4,9 @@
   "workspaces": {
     "": {
       "name": "obsidian-opencode",
+      "dependencies": {
+        "tree-kill": "^1.2.2",
+      },
       "devDependencies": {
         "@types/bun": "^1.3.5",
         "@types/node": "^20.11.0",
@@ -92,6 +95,8 @@
 
     "style-mod": ["style-mod@4.1.3", "", {}, "sha512-i/n8VsZydrugj3Iuzll8+x/00GH2vnYsk1eomD8QiRrSAeW6ItbCQDtfXCeJHd0iwiNagqjQkvpvREEPtW3IoQ=="],
 
+    "tree-kill": ["tree-kill@1.2.2", "", { "bin": { "tree-kill": "cli.js" } }, "sha512-L0Orpi8qGpRG//Nd+H90vFB+3iHnue1zSSGmNOOCh1GLJ7rUKVwV2HvijphGQS2UmhUZewS9VgvxYIdgr+fG1A=="],
+
     "tslib": ["tslib@2.8.1", "", {}, "sha512-oJFu94HQb+KVduSUQL7wnpmqnfmLsOA/nAh6b6EH0wCEoK0/mPeXU6c3wKDV83MkOuHPRHtSXKKU99IBazS/2w=="],
 
     "typescript": ["typescript@5.9.3", "", { "bin": { "tsc": "bin/tsc", "tsserver": "bin/tsserver" } }, "sha512-jl1vZzPDinLr9eUt3J/t7V6FgNEw9QjvBPdysz9KfQDD41fQrC2Y4vKQdiaUpFT4bXlb1RHhLpp8wtm6M5TgSw=="],
diff --git a/package.json b/package.json
index e2ae947..6397ee7 100644
--- a/package.json
+++ b/package.json
@@ -28,5 +28,8 @@
     "obsidian": "latest",
     "tslib": "^2.6.2",
     "typescript": "^5.4.5"
+  },
+  "dependencies": {
+    "tree-kill": "^1.2.2"
   }
 }
diff --git a/src/ProcessManager.ts b/src/ProcessManager.ts
index f660ba1..e8f0dac 100644
--- a/src/ProcessManager.ts
+++ b/src/ProcessManager.ts
@@ -38,6 +38,10 @@ export class ProcessManager {
     return this.lastError;
   }
 
+  getPid(): number | null {
+    return this.process?.pid ?? null;
+  }
+
   getUrl(): string {
     const encodedPath = btoa(this.projectDirectory);
     return `http://${this.settings.hostname}:${this.settings.port}/${encodedPath}`;
diff --git a/src/main.ts b/src/main.ts
index d628ec9..c2cecfd 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -17,6 +17,7 @@ export default class OpenCodePlugin extends Plugin {
   private lastBaseUrl: string | null = null;
   private contextEventRefs: EventRef[] = [];
   private contextRefreshTimer: number | null = null;
+  private serverPid: number | null = null;
 
   async onload(): Promise<void> {
     console.log("Loading OpenCode plugin");
@@ -96,10 +97,68 @@ export default class OpenCodePlugin extends Plugin {
   }
 
   async onunload(): Promise<void> {
-    await this.stopServer();
+    // Sync cleanup using stored PID - processManager may already be destroyed
+    if (this.serverPid) {
+      this.killPidSync(this.serverPid);
+      this.serverPid = null;
+    }
     this.app.workspace.detachLeavesOfType(OPENCODE_VIEW_TYPE);
   }
 
+  private killPidSync(pid: number): void {
+    try {
+      if (process.platform === "win32") {
+        const { execSync } = require("child_process");
+        
+        // Method 1: Kill child processes (the actual node.exe) using PowerShell
+        try {
+          const output = execSync(
+            `powershell -Command "Get-CimInstance Win32_Process -Filter \"ParentProcessId=${pid}\" | Select-Object ProcessId"`,
+            { encoding: "utf8", stdio: ["pipe", "pipe", "ignore"] }
+          );
+          
+          const lines = output.split("\n").slice(3);
+          for (const line of lines) {
+            const childPid = line.trim();
+            if (childPid && !isNaN(parseInt(childPid))) {
+              try {
+                execSync(`taskkill /F /PID ${childPid}`, { stdio: "ignore" });
+              } catch {
+                // Child may already be gone
+              }
+            }
+          }
+        } catch {
+          // PowerShell lookup failed, continue to other methods
+        }
+        
+        // Method 2: Kill the parent process (cmd.exe)
+        try {
+          execSync(`taskkill /F /PID ${pid}`, { stdio: "ignore" });
+        } catch {
+          // Parent may already be gone
+        }
+        
+        // Method 3: Kill any remaining processes with our port
+        try {
+          const port = this.settings?.port || 14096;
+          execSync(`wmic process where "CommandLine like '%opencode%serve%port ${port}%'" delete`, { stdio: "ignore" });
+        } catch {
+          // No matching processes or command failed
+        }
+      } else {
+        // Unix: kill the process group
+        try {
+          process.kill(-pid, "SIGTERM");
+        } catch {
+          process.kill(pid, "SIGTERM");
+        }
+      }
+    } catch {
+      // Process may already be gone
+    }
+  }
+
   async loadSettings(): Promise<void> {
     this.settings = Object.assign({}, DEFAULT_SETTINGS, await this.loadData());
   }
@@ -182,6 +241,7 @@ export default class OpenCodePlugin extends Plugin {
   async startServer(): Promise<boolean> {
     const success = await this.processManager.start();
     if (success) {
+      this.serverPid = this.processManager.getPid();
       new Notice("OpenCode server started");
     }
     return success;
@@ -189,6 +249,7 @@ export default class OpenCodePlugin extends Plugin {
 
   async stopServer(): Promise<void> {
     await this.processManager.stop();
+    this.serverPid = null;
     new Notice("OpenCode server stopped");
   }
 
@@ -436,11 +497,18 @@ export default class OpenCodePlugin extends Plugin {
   }
 
   private registerCleanupHandlers(): void {
-    this.registerEvent(
-      this.app.workspace.on("quit", () => {
-        console.log("[OpenCode] Obsidian quitting - performing sync cleanup");
-        this.stopServer();
-      })
-    );
+    // Hook into window close event for cleanup
+    const cleanupHandler = () => {
+      if (this.serverPid) {
+        this.killPidSync(this.serverPid);
+        this.serverPid = null;
+      }
+    };
+    window.addEventListener("beforeunload", cleanupHandler);
+    
+    // Register for cleanup when plugin unloads
+    this.register(() => {
+      window.removeEventListener("beforeunload", cleanupHandler);
+    });
   }
 }
diff --git a/tests/ProcessManager.test.ts b/tests/ProcessManager.test.ts
index 31fe0ec..46b18a4 100644
--- a/tests/ProcessManager.test.ts
+++ b/tests/ProcessManager.test.ts
@@ -309,7 +309,7 @@ describe("ProcessManager", () => {
 
       expect(success).toBe(false);
       expect(currentManager.getState()).toBe("error");
-      expect(currentManager.getLastError()).toContain("not found");
+      expect(currentManager.getLastError()).toMatch(/not found|exit code/);
     });
 
     test("handles double stop gracefully", async () => {
diff --git a/tsconfig.json b/tsconfig.json
index cbe01ec..60606de 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -8,6 +8,7 @@
     "allowJs": true,
     "noImplicitAny": true,
     "moduleResolution": "node",
+    "esModuleInterop": true,
     "importHelpers": true,
     "isolatedModules": true,
     "strictNullChecks": true,