diff --git a/java/net/i2p/router/WinLauncher.java b/java/net/i2p/router/WinLauncher.java
index 7b580e2..d982941 100644
--- a/java/net/i2p/router/WinLauncher.java
+++ b/java/net/i2p/router/WinLauncher.java
@@ -94,6 +94,12 @@ public class WinLauncher extends CopyConfigDir {
           "Service startup failure, please start I2P service with services.msc");
       System.exit(2);
     }
+    continuerunning = promptUserInstallStartIfAvailable();
+    if (!continuerunning) {
+      logger.severe(
+          "User-install startup required.");
+      System.exit(2);
+    }
 
     // This actually does most of what we use NSIS for if NSIS hasn't
     // already done it, which essentially makes this whole thing portable.
diff --git a/java/net/i2p/router/WindowsServiceUtil.java b/java/net/i2p/router/WindowsServiceUtil.java
index 03347ec..b7d8fff 100644
--- a/java/net/i2p/router/WindowsServiceUtil.java
+++ b/java/net/i2p/router/WindowsServiceUtil.java
@@ -1,6 +1,7 @@
 package net.i2p.router;
 
 import java.io.BufferedReader;
+import java.io.File;
 import java.io.IOException;
 import java.io.InputStreamReader;
 import javax.swing.JOptionPane;
@@ -142,6 +143,48 @@ public class WindowsServiceUtil {
     return "http://tc73n4kivdroccekirco7rhgxdg5f3cjvbaapabupeyzrqwv5guq.b32.i2p/news.su3";
   }
 
+  public static boolean checkProgramFilesInstall() {
+    String programFiles = System.getenv("PROGRAMFILES");
+    File programFilesI2P = new File(programFiles, "i2p/i2p.exe");
+    if (programFilesI2P.exists())
+      return true;
+    String programFiles86 = System.getenv("PROGRAMFILES86");
+    File programFiles86I2P = new File(programFiles86, "i2p/i2p.exe");
+    if (programFiles86I2P.exists())
+      return true;
+    return false;
+  }
+
+  public static boolean promptUserInstallStartIfAvailable() {
+    if (osName() != "windows") {
+      return true;
+    }
+    if (checkProgramFilesInstall()) {
+      int a;
+      String message =
+          "It appears you have an existing, unbundled I2P rotuer installed.\n";
+      message +=
+          "However, it is not running yet. Please start it using the shortcut on the desktop.\n";
+      message +=
+          "If you click \"No\", the jpackage router will be launched instead.\n";
+      a = JOptionPane.showConfirmDialog(null, message,
+                                        "I2P Service detected not running",
+                                        JOptionPane.YES_NO_OPTION);
+      if (a == JOptionPane.NO_OPTION) {
+        // Do nothing here, this will continue on to launch a jpackaged router
+        return true;
+      } else {
+        // We can't just call `net start` or `sc start` directly, that throws
+        // a permission error. We can start services.msc though, where the
+        // user can start the service themselves. OR maybe we ask for
+        // elevation here? May need to refactor Elevator and Shell32X to
+        // achieve it though
+        return false;
+      }
+    }
+    return true;
+  }
+
   public static String getServiceState(String serviceName) {
     String stateString = "uninstalled";
     int state = getServiceStateInt(serviceName);