Enable or disable pop-up reminders for Tasks and Events

Turn On Pop-Up Reminders for Tasks and Events

1. Click the Gear icon on top right and navigate to Setup and enter Activity Settings in the Quick Find box. 
2. Click Activity Settings.
3. Select Enable Activity Reminders.
4. Click Submit.

Note: To receive reminder pop-up notifications, your pop-up blocker must be disabled.

Turn Off Pop-Up Reminders for Tasks and Events

1. Navigate to Setup and enter Activity Settings in the Quick Find box.
2. Click Activity Settings.
3. Deselect Enable Activity Reminders.
4. Click Submit.

Notes:

• This is applicable to both Salesforce Classic and Lightning Experience.
• Activity reminder pop-ups will not display if the only page open in the org was created with Visualforce (*.visual.force.com).