diff --git a/src/lib/onboard/windows-host-ollama.test.ts b/src/lib/onboard/windows-host-ollama.test.ts
new file mode 100644
index 0000000000..da12abcef8
--- /dev/null
+++ b/src/lib/onboard/windows-host-ollama.test.ts
@@ -0,0 +1,43 @@
+// SPDX-FileCopyrightText: Copyright (c) 2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+import { afterEach, describe, expect, it, vi } from "vitest";
+
+const runCapture = vi.fn<(cmd: readonly string[]) => string>(() => "");
+
+vi.mock("../runner", () => ({
+  runCapture: (cmd: readonly string[]) => runCapture(cmd),
+}));
+
+vi.mock("../platform", () => ({
+  isWsl: vi.fn(() => true),
+}));
+
+import { isWsl } from "../platform";
+import { detectWindowsHostOllama } from "./windows-host-ollama";
+
+describe("detectWindowsHostOllama", () => {
+  afterEach(() => {
+    vi.clearAllMocks();
+    vi.mocked(isWsl).mockReturnValue(true);
+  });
+
+  it("detects installed-but-not-running Ollama via known install path (#4066)", () => {
+    const knownPath = "C:\\Users\\tester\\AppData\\Local\\Programs\\Ollama\\ollama.exe";
+    runCapture.mockImplementation((command: readonly string[]) => {
+      const cmd = command.join(" ");
+      if (cmd.includes("Get-Command ollama.exe")) return "";
+      if (cmd.includes("Get-Process ollama") && cmd.includes("Path")) return "";
+      if (cmd.includes("Get-Process ollama") && cmd.includes("Id")) return "";
+      if (cmd.includes("Test-Path -LiteralPath")) return knownPath;
+      if (cmd.includes("Get-NetTCPConnection")) return "";
+      return "";
+    });
+
+    expect(detectWindowsHostOllama()).toEqual({
+      installed: true,
+      installedPath: knownPath,
+      loopbackOnly: false,
+    });
+  });
+});
diff --git a/src/lib/onboard/windows-host-ollama.ts b/src/lib/onboard/windows-host-ollama.ts
index e131c4d5ee..a496d34887 100644
--- a/src/lib/onboard/windows-host-ollama.ts
+++ b/src/lib/onboard/windows-host-ollama.ts
@@ -55,12 +55,9 @@ function probeInstalledPath(): string {
   // lookup (#3949).
   const processPath = powershell(GET_PROCESS_OLLAMA_PATH);
   if (processPath.length > 0) return processPath;
-  // Some WSL-launched PowerShell sessions can see the Windows ollama PID
-  // but cannot read the Path property. Only after observing the live
-  // daemon, fall back to fixed installer locations so the restart path
-  // still has an explicit executable to launch.
-  const pid = powershell(GET_PROCESS_OLLAMA_ID);
-  if (!pid) return "";
+  // Silent installs often land in fixed locations without updating PATH or
+  // leaving a running daemon to probe. Check those paths even when no PID is
+  // visible so WSL onboarding offers Start instead of Install (#4066).
   return powershell(GET_KNOWN_OLLAMA_INSTALL_PATH);
 }