# Flow fault paths, debugging and run monitoring

*Platform App Builder Study Guide · Business Logic and Process Automation · Last updated October 25, 2026 · https://www.certifyforce.com/study-guide/platform-app-builder/business-logic-and-process-automation/flow-fault-paths-debugging-and-run-monitoring*

What happens when a flow fails with and without a fault path, who gets the error email, how to debug safely and as another user, and which tools show trigger order, dependencies, version changes and run health.

- Certification: Salesforce Platform App Builder
- Exam section: Business Logic and Process Automation
- Study guide: https://www.certifyforce.com/study-guide/platform-app-builder

**Official exam objective:**

> Maintain, monitor, and troubleshoot flows.

## What the exam expects

- Predict what a user sees and what is rolled back when a flow element fails, with no fault path or with one, for record-triggered, screen and autolaunched flows.
- Use Custom Error and Roll Back Records in fault paths, and log failures against the interview GUID.
- Route flow error emails and apply the troubleshooting checklist, including shared CPU limits.
- Debug safely: rollback mode, debugging as another user, Debug versus Test Mode.
- Pick the monitoring tool: Flow Trigger Explorer and trigger order, Compare Versions, the Usage tab, Element Error Rate and on-canvas run data.

Key terms: **fault path** (the connector an element follows when it fails); **unhandled fault** (a failure with no or an empty fault path); **flow interview** (one running instance of a flow); **interview GUID** (the identifier every interview has); **trigger order** (1-2,000 value that sequences record-triggered flows); **rollback mode** (a debug option that undoes the run's changes).

## Key facts

| Fact | Detail | Source |
|---|---|---|
| Record-triggered flow, no fault path | Change blocked and rolled back; a validation rule's message replaces the generic one | [Default Flow Error Handling](https://help.salesforce.com/s/articleView?id=platform.flow_build_logic_fault_default.htm&language=en_US&type=5) |
| Screen flow fault path | Completion message if no Screen; rollback only with Roll Back Records | [Default Flow Error Handling](https://help.salesforce.com/s/articleView?id=platform.flow_build_logic_fault_default.htm&language=en_US&type=5) |
| Custom Error element | Record-triggered flows only | [Flow Types](https://help.salesforce.com/s/articleView?id=platform.flow_concepts_type.htm&language=en_US&type=5) |
| Error email recipients | Last modifier of the flow, or Apex exception email recipients | [Troubleshooting Flow Run Time Errors](https://help.salesforce.com/s/articleView?language=en_US&id=flow_troubleshoot_email.htm) |
| Interview identifier for logs | GUID; Salesforce ID only once paused | [Troubleshooting Flow Run Time Errors](https://help.salesforce.com/s/articleView?language=en_US&id=flow_troubleshoot_email.htm) |
| CPU time limit | Shared with all automation in the transaction, including Apex triggers | [Troubleshooting Flow Run Time Errors](https://help.salesforce.com/s/articleView?language=en_US&id=flow_troubleshoot_email.htm) |
| Debug as another user | One-time admin setup; sandboxes only | [Flow Builder Debugger](https://help.salesforce.com/s/articleView?id=platform.flow_test_debug.htm&type=5) |
| Trigger order range | 1 to 2,000; ties alphabetical by API name | [Run Order](https://help.salesforce.com/s/articleView?language=en_US&id=platform.flow_task_trigger_run_order.htm) |

## Check yourself

- Why might a flow that passes in the debugger fail during a bulk update?
- When does a screen flow fault path roll back earlier changes?
- Who can receive flow error emails?
- When do flows with no trigger order value run?
- Which tool shows the automations that call a flow before you deactivate it?

## Sources

- [Default Flow Error Handling](https://help.salesforce.com/s/articleView?id=platform.flow_build_logic_fault_default.htm&language=en_US&type=5)
- [Troubleshooting Flow Run Time Errors](https://help.salesforce.com/s/articleView?language=en_US&id=flow_troubleshoot_email.htm)
- [Managing and Monitoring Flows](https://help.salesforce.com/s/articleView?language=en_US&id=platform.flow_monitor.htm&type=5)
- [Test or Troubleshoot Flows with the Flow Builder Debugger](https://help.salesforce.com/s/articleView?id=platform.flow_test_debug.htm&type=5)
- [Manage Record-Triggered Flows](https://help.salesforce.com/s/articleView?id=platform.flow_trigger_explorer.htm)
- [Define the Run Order of Record-Triggered Flows for an Object](https://help.salesforce.com/s/articleView?language=en_US&id=platform.flow_task_trigger_run_order.htm)
- [Compare Flow Versions to Track Changes](https://help.salesforce.com/s/articleView?id=platform.automate_flow_manage_compare_versions.htm&language=en_US&type=5)
- [Flow Types](https://help.salesforce.com/s/articleView?id=platform.flow_concepts_type.htm&language=en_US&type=5)

## About the full unit

The "Core concepts", "Exam traps" and "Worked scenario" sections of this unit, its 14 linked practice questions, and unlimited timed mock exams are included with the Platform App Builder pack (USD $19): https://www.certifyforce.com/practice-exams