diff --git a/app/src/main/java/com/limelight/binding/input/driver/UsbDriverService.java b/app/src/main/java/com/limelight/binding/input/driver/UsbDriverService.java
index 1adaf582..d4f16275 100644
--- a/app/src/main/java/com/limelight/binding/input/driver/UsbDriverService.java
+++ b/app/src/main/java/com/limelight/binding/input/driver/UsbDriverService.java
@@ -14,8 +14,10 @@ import android.os.Build;
 import android.os.Handler;
 import android.os.IBinder;
 import android.view.InputDevice;
+import android.widget.Toast;
 
 import com.limelight.LimeLog;
+import com.limelight.R;
 
 import java.util.ArrayList;
 
@@ -121,7 +123,17 @@ public class UsbDriverService extends Service implements UsbDriverListener {
             // Do we have permission yet?
             if (!usbManager.hasPermission(device)) {
                 // Let's ask for permission
-                usbManager.requestPermission(device, PendingIntent.getBroadcast(UsbDriverService.this, 0, new Intent(ACTION_USB_PERMISSION), 0));
+                try {
+                    // This function is not documented as throwing any exceptions (denying access
+                    // is indicated by calling the PendingIntent with a false result). However,
+                    // Samsung Knox has some policies which block this request, but rather than
+                    // just returning a false result or returning 0 enumerated devices,
+                    // they throw an undocumented SecurityException from this call, crashing
+                    // the whole app. :(
+                    usbManager.requestPermission(device, PendingIntent.getBroadcast(UsbDriverService.this, 0, new Intent(ACTION_USB_PERMISSION), 0));
+                } catch (SecurityException e) {
+                    Toast.makeText(this, this.getText(R.string.error_usb_prohibited), Toast.LENGTH_LONG).show();
+                }
                 return;
             }
 
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index 8b81b333..01399fe5 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -51,6 +51,7 @@
     <string name="message_decoding_error">Moonlight has crashed due to a problem with this device\'s video decoder. Try adjusting the streaming settings if the crashes continue.</string>
     <string name="title_decoding_reset">Video Settings Reset</string>
     <string name="message_decoding_reset">Your device\'s video decoder continues to crash at your selected streaming settings. Your streaming settings have been reset to default.</string>
+    <string name="error_usb_prohibited">USB access is prohibited by your device administrator. Check your Knox or MDM settings.</string>
 
     <!-- Start application messages -->
     <string name="conn_establishing_title">Establishing Connection</string>