Logitech Signature Comfort M840 L Wireless Mouse User Manual

1. Setup

This section guides you through the initial setup of your Logitech Signature Comfort M840 L Wireless Mouse.

1.1. Battery Installation

Your mouse comes with one AA alkaline battery pre-installed. To activate the mouse, remove any protective pull-tabs from the battery compartment. If replacing the battery, open the battery compartment cover located on the underside of the mouse, insert one AA battery with the correct polarity, and close the cover.

Image: Top and bottom view of the M840 L mouse, highlighting the battery compartment and indicating a 24-month battery life.

1.2. Connecting Your Mouse

The M840 L mouse connects wirelessly via Bluetooth. No USB dongle is required.

1. Power On: Ensure the mouse is powered on using the switch on the bottom.
2. Activate Pairing Mode: Press and hold the Easy-Switch button (usually located on the bottom or side of the mouse) until the LED indicator starts blinking rapidly. This indicates the mouse is in pairing mode.
3. Device Pairing: On your computer or device, navigate to Bluetooth settings and select 'Add a device' or 'Pair new device'. Choose 'Logitech M840 L' from the list of available devices.
4. Confirmation: The LED indicator on the mouse will turn solid for a few seconds, then turn off, confirming a successful connection.

Image: An overview of the M840 L mouse highlighting its key features including Bluetooth connectivity.

1.3. Multi-Device Pairing (Easy-Switch)

The M840 L supports connecting to up to three devices simultaneously using the Easy-Switch feature.

1. Pair First Device: Follow the steps in 1.2 to pair your first device.
2. Switch Channel: Press the Easy-Switch button briefly to switch to an unoccupied channel (e.g., if channel 1 is used, switch to 2 or 3). The LED for the selected channel will blink slowly.
3. Pair Second/Third Device: Press and hold the Easy-Switch button for the new channel until its LED blinks rapidly, then pair with your second device as described in 1.2. Repeat for a third device if needed.
4. Switching Between Devices: To switch between paired devices, simply press the Easy-Switch button briefly to select the desired channel.

Image: A user seamlessly switching between a laptop and a desktop setup using the Easy-Switch feature of the M840 L mouse.

1.4. Software Installation (Logi Options+)

For full customization of buttons and advanced features, download and install the Logi Options+ software from the official Logitech website. This software is compatible with Windows and macOS.

2. Operating Instructions

Learn how to use the various features of your M840 L mouse for optimal productivity.

2.1. Basic Functions

• Left Click: Primary selection and activation.
• Right Click: Accesses contextual menus.
• Middle Click (Scroll Wheel Press): Can be customized via Logi Options+ for various functions like opening new tabs or universal scroll.
• Side Buttons: Default to Forward/Back navigation in web browsers. Customizable via Logi Options+.

Image: A hand demonstrating the comfortable grip of the M840 L mouse, designed for right-handed use.

2.2. SmartWheel Scrolling

The SmartWheel automatically switches between two scrolling modes:

• Line-by-Line Scrolling: Ideal for precise navigation through documents and lists.
• Hyper-Fast Scrolling: Automatically engages when you scroll faster, allowing you to fly through long web pages and documents.

The M840 L also features quiet clicks and scrolling, minimizing distractions in shared workspaces.

Image: A user engaging the SmartWheel for efficient scrolling, maintaining focus during work.

2.3. Customizing Buttons with Logi Options+

Utilize the Logi Options+ software to personalize your mouse experience:

• Button Assignments: Reassign functions to any of the 6 buttons, including application-specific actions.
• DPI Adjustment: Fine-tune the mouse's tracking speed (DPI) to match your preference.
• Gestures: Assign gesture controls to certain buttons for enhanced navigation.
• Flow: If you have multiple computers with Logi Options+ installed, use Flow to seamlessly move your cursor, text, and files between them.

Image: A user interacting with the Logi Options+ app to customize the buttons of their M840 L mouse for improved workflow.

3. Maintenance

Proper maintenance ensures the longevity and optimal performance of your mouse.

3.1. Battery Replacement

The M840 L mouse has an estimated battery life of up to 24 months. When the battery is low, the LED indicator on the mouse may flash red. To replace the battery:

1. Turn off the mouse using the power switch on the bottom.
2. Open the battery compartment cover on the underside of the mouse.
3. Remove the old AA battery.
4. Insert a new AA alkaline battery, ensuring correct polarity (+/-).
5. Close the battery compartment cover.
6. Turn the mouse back on.

3.2. Cleaning

To clean your mouse, use a soft, lint-free cloth lightly dampened with water or an electronics-safe cleaning solution. Avoid harsh chemicals, abrasive materials, or excessive moisture. Regularly clean the optical sensor on the bottom of the mouse to ensure accurate tracking.

4. Troubleshooting

If you encounter issues with your M840 L mouse, refer to the following common solutions.

4.1. Mouse Not Responding

• Check Power: Ensure the mouse is turned on.
• Battery Level: Replace the AA battery if it is low or depleted.
• Re-pair Bluetooth: Go to your device's Bluetooth settings, remove the M840 L, and then re-pair it following the steps in Section 1.2.
• Try Another Device: Test the mouse with another Bluetooth-enabled device to determine if the issue is with the mouse or the original device.

4.2. Intermittent Connection or Lag

• Reduce Interference: Move the mouse closer to your device. Avoid using the mouse near other wireless devices (Wi-Fi routers, cordless phones) that might cause interference.
• Update Drivers: Ensure your computer's Bluetooth drivers are up to date.
• Clean Sensor: Clean the optical sensor on the bottom of the mouse.

4.3. Buttons Not Functioning as Expected

• Check Logi Options+: Open the Logi Options+ software to verify button assignments. Ensure no conflicting profiles are active.
• Software Reinstallation: If issues persist, try uninstalling and reinstalling Logi Options+.

5. Specifications

6. Warranty and Support

6.1. Warranty Information

The Logitech Signature Comfort M840 L Wireless Mouse comes with a 2-Year Limited Hardware Warranty. This warranty covers defects in materials and workmanship under normal use. For full terms and conditions, please refer to the documentation included with your product or visit the official Logitech website.

6.2. Customer Support

For further assistance, technical support, or to download the latest version of Logi Options+ software, please visit the official Logitech support website:

• Logitech Support: https://support.logi.com
• Logi Options+ Download: https://www.logitech.com/optionsplus