Missing required field – A required field for an action was left blank.

In Power Automate, each action in a flow requires specific fields to be filled for successful execution. If any mandatory field is left blank or does not contain valid data, you may encounter the following error:

“Missing required field – A required field for an action was left blank.”

This error means that the action could not complete because a necessary input parameter is missing or incorrectly formatted.

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2. Causes of “Missing Required Field” Error

Several factors can trigger this issue:

1. Manually Left Blank Fields – Required fields were not populated during flow creation.
2. Dynamic Content Not Resolved – A previous step did not return the expected value.
3. Null or Empty Value from a Trigger or Action – The input data does not contain the expected field.
4. Incorrect Data Type – The provided value is not in the expected format.
5. Data Source Changes – A SharePoint list, Dataverse table, or SQL database structure changed.
6. Permissions Issue – The flow does not have access to retrieve data from a source.
7. Expression Errors – Incorrectly written expressions returning null or empty values.

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3. Step-by-Step Troubleshooting Guide

Step 1: Identify the Failing Action

1. Open Power Automate (https://flow.microsoft.com).
2. Navigate to My Flows and select the affected flow.
3. Click Run History and find the failed run.
4. Expand the failed action to see the error message.

Solution:

• Look for which field is missing in the Inputs section.
• Compare it with the expected values.

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Step 2: Check for Empty or Unresolved Dynamic Content

If a required field is populated using dynamic content but appears blank, the issue might be with a previous step.

Solution:

1. Expand the failed action and check the Inputs section.
2. Verify that the dynamic content used in the field contains data.
3. If the value is missing, check the previous action’s output.

Example:

• If using Get Items from SharePoint, but no items exist, dynamic fields may be empty in the next step.

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Step 3: Verify Data Types and Default Values

If a field requires a specific data type (text, number, date) and receives the wrong type, it may cause an error.

Solution:

• Ensure that numeric fields contain numbers and date fields contain valid date formats.
• Use Power Automate expressions to convert values: int(variables('YourVariable')) // Convert to integer string(variables('YourVariable')) // Convert to string formatDateTime(utcNow(), 'yyyy-MM-dd') // Convert to date format

Example:

• If a Create Record in Dataverse action expects a date but receives text, it will fail.

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Step 4: Check for Null or Empty Values in Triggers

Some flows fail when an input value is missing because the trigger did not return expected data.

Solution:

1. Add a condition step before using the field:
   • if(empty(triggerOutputs()?['body/fieldname']), 'Default Value', triggerOutputs()?['body/fieldname'])
2. Use the “Coalesce” function to provide a default value: coalesce(triggerOutputs()?['body/fieldname'], 'Default Value')

Example:

• If a Power Apps trigger does not send a value for an expected field, the flow will fail unless a default is set.

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Step 5: Ensure Data Sources Have Not Changed

If the flow is connected to SharePoint, Dataverse, SQL Server, or Excel, ensure the data structure has not changed.

Solution:

1. Open the data source and verify that the required field still exists.
2. If the field was renamed or deleted, update the action in Power Automate.
3. Refresh the connection to the data source.

Example:

• If a SharePoint column was deleted, an action expecting that column will fail.

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Step 6: Verify Permissions and Access Rights

If the flow does not have permission to retrieve or write data, required fields may appear missing.

Solution:

1. Ensure the Power Automate user account has correct permissions.
2. Re-authenticate the connection in Power Automate.
3. Check API permissions if using external services.

Example:

• If a SharePoint action fails due to missing permissions, ensure the user has “Contribute” rights.

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Step 7: Rebuild the Action to Refresh Field Mappings

If an action was modified and now shows missing fields, deleting and re-adding it can resolve the issue.

Solution:

1. Delete the failing action.
2. Add the action again and reconfigure the required fields.
3. Save and test the flow.

Example:

• If a Dataverse action fails after a schema change, recreating it updates the mappings.

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Step 8: Use Default Values to Avoid Missing Fields

To prevent missing fields, use default values or validation checks.

Solution:

• Use a condition to check if a field is empty before using it.
• Provide a default value using expressions like: if(empty(variables('YourVariable')), 'Default Value', variables('YourVariable'))

Example:

• If a form submission does not contain a phone number, set a default like “Not Provided”.

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4. Preventative Measures

To prevent “Missing Required Field” errors in the future:

✔ Always populate required fields in Power Automate actions.
✔ Check dynamic content to ensure it is resolving correctly.
✔ Use default values for fields that may sometimes be empty.
✔ Ensure that data types match the field requirements.
✔ Monitor changes to data sources and update flows accordingly.
✔ Test the flow regularly with different input scenarios.