How to Fix CH340 Driver Installation Failure on Longer Laser Engravers

Introduction

This document summarizes the common causes and solutions for CH340 driver installation issues on both Windows and macOS systems. It explains how to resolve problems related to system compatibility, driver conflicts, permission restrictions, USB cable issues, and security settings. It also provides methods to verify whether the driver is installed correctly and suggests alternative solutions if installation continues to fail.

By following the troubleshooting steps in this guide, users can quickly diagnose driver installation problems and restore normal communication between their device and computer.

Windows System

Common Causes and Solutions

1. System Compatibility Issues

Windows 10 and Windows 11 usually include a built-in driver for the CH340 chip. However, automatic installation may occasionally fail.

Solution

Download and install the latest driver manually from the official website:
https://www.wch.cn

Install the latest version of the driver package CH341SER.EXE.

2. Old Driver Conflicts

If an older version of the CH340 driver was previously installed, it may conflict with the new installation.

Solution

1. Open Device Manager.

2. Click View → Show hidden devices.

3. Expand Ports (COM & LPT).

4. Right-click any CH340/CH341 related devices and uninstall them.

5. Select Delete the driver software for this device if prompted.

6. Reinstall the latest driver.

3. Driver Signature Issues

Some systems, especially Windows 7 and certain Windows 10 configurations, may block unsigned drivers.

Solution

1. Restart your computer.

2. Enter Advanced Startup Options.

3. Select Disable driver signature enforcement.

4. Run the driver installer again.

4. Insufficient Permissions

Installing drivers requires administrator privileges.

Solution

Right-click the installer and select Run as administrator.

5. USB Cable or Port Problems

Some USB cables only support charging and do not transfer data. If such a cable is used, the device will not be recognized even if the driver is installed.

Solution

• Use a USB cable that supports data transfer.

• Connect the cable directly to the computer’s USB port (preferably USB 2.0).

How to Confirm the Driver Installation

1. Connect the Longer laser engraver to your computer.

2. Open Device Manager.

Under Ports (COM & LPT) you should see something similar to:

USB-SERIAL CH340 (COM3)

If this appears, the driver has been installed successfully.

If a yellow warning icon appears, the driver installation may have failed or there may be a driver conflict.

Alternative Solutions

If the driver still cannot be installed:

• Try using another computer to rule out system-related issues.

• Replace the adapter module with FT232 or CP2102, which often offer better compatibility.

macOS System

1. Check Whether a Driver Is Needed

Starting from macOS 10.13, the CH340 chip may sometimes be recognized automatically without installing a driver.

1. Connect your Longer laser engraver.

2. Open Terminal and enter:

ls /dev/tty.*

If you see a device such as:

/dev/tty.wchusbserial1410

The device has been detected successfully and no driver installation is required.

2. Install the Driver (If the Device Is Not Recognized)

Download the Driver

Official driver
https://www.wch.cn/downloads/CH341SER_MAC_ZIP.html

Open-source driver (recommended)
https://github.com/adrianmihalko/ch340g-ch34g-ch34x-mac-os-x-driver

The open-source version often provides better compatibility with newer macOS systems.

Allow System Extensions

During installation, macOS may display a message such as “System Extension Blocked.”

To allow the driver:

1. Open System Settings / System Preferences.

2. Go to Security & Privacy.

3. Under the General tab, click Allow for WCH Electronics Co., Ltd.

Restart Your Computer

After installation, restart your Mac so the driver can be loaded correctly.

Troubleshooting Common Issues

Driver Installed but No Port Appears

Open Terminal and run:

ls /dev/tty.*

Disconnect and reconnect the USB cable to check whether a new device appears.

Apple Silicon Macs (M1 / M2 / M3)

Many official drivers were originally designed for Intel-based Macs, which may cause compatibility issues on Apple Silicon devices.

For better stability, we recommend using the open-source driver from GitHub mentioned above.

Permission Restrictions on New macOS Versions

Recent macOS versions such as Big Sur, Monterey, and Ventura enforce stricter security policies for third-party drivers.

If the Allow option does not appear in Security & Privacy, you may need to:

1. Restart your Mac in Recovery Mode.

2. Temporarily disable System Integrity Protection (SIP).

3. Install the driver again.

Alternative Options

If you still cannot install the CH340 driver, you may consider these alternatives:

• Use an FTDI USB-to-serial module, which macOS supports natively without additional drivers.

• Use a Wi-Fi connection if your GRBL controller board supports wireless communication.