# UltraVNC Extend Display - Frequently Asked Questions

## Where are the logs?

Server/service logs are written to:

```text
C:\ProgramData\UVNCExtDisp\service.log
C:\ProgramData\UVNCExtDisp\helper.log
```

If the service cannot write there, it falls back to:

```text
C:\Windows\Temp\UVNCExtDisp_service.log
```

## The client says "No UltraVNC Extend Display server found on the LAN"

- Make sure the desktop PC has the service installed and running:

  ```cmd
  sc.exe query UVNCExtDisp
  ```

- If it is `STOPPED`, start it from an elevated prompt:

  ```cmd
  sc.exe start UVNCExtDisp
  ```

- Make sure both PCs are on the same network and the firewall allows TCP 5950 and UDP 5951.

- If the desktop PC was locked, unlock it. The service does not stream a locked session for security reasons; the client reconnects automatically once unlocked.

## Does the client connect automatically?

Yes. When you run `ultravnc_extdisp.exe` without a host name, it auto-discovers a server on the LAN and connects immediately. If you click **Discover** in the connect dialog, it also connects automatically as soon as a server is found.

## Why does the extra monitor freeze when the desktop PC is locked?

Windows blanks the DXGI Desktop Duplication feed while the session is locked. This is an OS-level limitation, not a bug in UltraVNC Extend Display. The client automatically resumes when the session is unlocked.

## Can I use this over the Internet or through NAT?

No. v1 is LAN only. Future versions may add repeater or relay support.

## Does the client send keyboard/mouse/touch input back to the desktop?

No. The client is display-only. It is intended to be an extra monitor, not a remote-control session.

## Do I need to run the client as Administrator?

No. Only the server/service needs elevation (for the virtual-display driver and the Windows service).

## Is the driver signed?

Yes. The package included in the installer is signed by uvnc bvba.

## I uninstalled but the service is still listed?

Run an elevated Command Prompt and remove it manually:

```cmd
sc.exe stop UVNCExtDisp
sc.exe delete UVNCExtDisp
```