Accurate CRM data isn’t just about what’s won—it’s also about understanding why deals are lost. Capturing the reason behind lost opportunities is essential for sales analysis, process improvement, and better forecasting. But unless it’s enforced, users often skip this step, leaving your data incomplete and your insights limited.
In this blog, we walk through an Apex trigger that requires users to fill in the “Closed Lost Reason” field whenever an Opportunity’s Stage is changed to “Closed Lost.” If the field is left empty, the user is prompted with an error, and the update is blocked until the reason is provided.
This trigger runs during the before update context, ensuring that your CRM captures meaningful data at the exact moment a deal is marked as lost—whether manually, through automation, or external integrations.
🧠 Why This Trigger Is Important
Knowing why opportunities are lost helps your sales organization:
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Adjust strategies to reduce future losses
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Identify competitive gaps or pricing issues
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Improve product offerings or positioning
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Coach sales reps on objections and deal handling
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Strengthen pipeline quality over time
If users skip the “Closed Lost Reason” field, you’re left with half the story—and your leadership team can’t make fully informed decisions.
With this trigger in place:
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Opportunities cannot be saved as “Closed Lost” without a reason
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Sales managers get better insights during pipeline reviews
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Sales teams develop a feedback loop to learn from every lost deal
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Reporting becomes more meaningful and actionable
🔍 What This Blog Covers
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How to use a before update trigger to enforce field validation
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How to detect when an Opportunity’s stage is changed to “Closed Lost”
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Why conditional validation is better than just making a field required on layout
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How to provide users with clear, immediate error messages
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How to organize Apex logic in a clean handler class for future reuse
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Where this validation fits into the broader opportunity lifecycle
This pattern supports proactive, disciplined data capture without burdening users with unnecessary prompts during other updates.
🎯 Real-World Use Cases for This Trigger
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Sales managers collecting win/loss feedback for pipeline optimization
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Sales enablement teams analyzing reasons behind deal drop-off
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Revenue operations standardizing close process compliance
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Executive leaders reviewing dashboards with clear loss categorization
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Organizations with coaching-driven cultures looking to support sales reps post-deal
This trigger is especially useful for B2B organizations, high-ticket sales cycles, or any environment where understanding loss trends is key to growth.
👨💻 Developer & Admin Tips
The trigger runs in the before update context on the Opportunity object. It checks:
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If the current stage is set to Closed Lost
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If the previous stage was different
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And if the Closed Lost Reason field is empty
If all conditions are met, the trigger throws an error message to the user:
“Please populate Closed Lost Reason.”
This message prevents the update from saving, guiding the user to complete the necessary field before proceeding.
Using a trigger handler method (populateClosedReason) keeps your logic modular and easy to test. You can also:
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Customize the error message to reflect internal naming conventions
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Extend the validation to ensure the reason is selected from a picklist
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Add exceptions for automated system processes if needed
Always test this trigger in scenarios such as:
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Manual updates from the UI
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Mass updates through imports or flows
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Integration-based updates from external systems
This ensures consistent enforcement across every entry point.
🎥 Walkthrough Available – YouTube Playlist
To see this trigger in action, head over to the Salesforce Makes Sense YouTube Playlist, where you’ll find a step-by-step demo showing:
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How the validation works during stage changes
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How to test and confirm the logic in your sandbox
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How to structure the handler for maintainability
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Tips on enhancing user experience through messaging
The playlist is designed to make real-world Salesforce automation easy to understand and apply—no jargon, just clarity.
Solution:
trigger OpportunityTrigger on Opportunity (before update) {
if(Trigger.isUpdate){ if(Trigger.isBefore){
OpportunityTriggerHandler.populateClosedReason(Trigger.New , Trigger.oldMap);
}
}
}
public class OpportunityTriggerHandler { public static void
populateClosedReason(List oppList,
Map<Id,Opportunity> oldMap){ for(Opportunity opp:oppList){
if(opp.StageName == ‘Closed Lost’ && opp.StageName != oldMap.get(opp.Id).StageName
&&
opp.Closed_Lost_Reason__c == null){ opp.addError(‘Please
populate Closed Lost Reason’);
}
}
}
}