Why Required Column Blocks Power Automate Updates

When you run a Power Automate flow that updates a SharePoint list item, the flow may fail with a generic error message like “Bad Gateway” or “Item does not exist”. One common hidden cause is a required column that the flow does not supply. SharePoint enforces column requirements during updates just as it does during new item creation. This article explains why required columns block Power Automate updates and shows you how to identify and fix the issue.

Why Required Columns Block Power Automate Updates

SharePoint list columns marked as Require that this column contains information enforce a validation rule at the server level. When Power Automate uses the Update item action, it sends a POST or MERGE request that SharePoint interprets as a full update attempt. If the request body does not include the required column, SharePoint returns an HTTP 400 or 403 error, and the flow fails.

This behavior is by design. SharePoint does not distinguish between a new item and an existing item when validating required columns — it checks every write operation. Power Automate’s Update item action does not automatically include all existing column values. It sends only the columns you explicitly map in the action. If you omit a required column, the server rejects the update.

The issue is most common when:

• A list administrator adds a new required column after flows are already running.
• A flow updates a subset of columns and the designer forgets to include an existing required column.
• A lookup or choice column is set as required and the flow uses a dynamic value that resolves to null.

Steps to Identify and Fix the Required Column Issue

Follow these steps to find the blocking column and update your flow.

1. Check the flow run history
   In Power Automate, open your flow and select Run history. Find the failed run and click it. Under Action outputs, look for the Update item action. The error message often lists the column name that caused the failure. Common error text includes “Required field” or “The specified column is required”.
2. Open the SharePoint list settings
   Go to the SharePoint site that hosts the list. Open the list, click the gear icon, and select List settings. Under Columns, look for columns with a checkmark in the Required column. Note every required column name.
3. Compare required columns to flow action inputs
   Return to Power Automate. Open the flow in edit mode. Click the Update item action. Review every field in the Advanced parameters section. Compare the list of mapped columns to the required columns from step 2. Any required column that is missing from the action will block the update.
4. Add the missing required column to the flow
   In the Update item action, click Show advanced options if it is collapsed. Find the missing column in the parameter list. If the column is not listed, click Add new parameter and select the column name. Provide a value. For an existing item, you can use the Get item action before the update to retrieve the current value and pass it through.
5. Add a Get item action before the update
   Insert a Get item action above the Update item action. Configure it with the same list and item ID. Then, in the Update item action, set the missing required column to the value from Get item. This ensures the existing value is preserved while you update other fields.
6. Test the flow
   Save the flow and run it against a test item. Check the run history to confirm the update succeeds. If the flow still fails, repeat steps 1 through 5 — there may be more than one missing required column.

If Power Automate Still Fails After Adding Required Columns

“Bad Gateway” error persists

A Bad Gateway error often indicates a time-out or connectivity issue, not a column validation problem. Check the SharePoint server load and retry the flow. If the error continues, use the Send an HTTP request to SharePoint action as an alternative.

Flow updates the wrong item or no item

The Update item action requires a valid item ID. If the ID is dynamic, verify that the previous action returns the correct ID. Use a Compose action to output the ID and check it in the run history.

Column value is a lookup or person field

Lookup and person columns require the internal ID of the referenced item, not the display name. If you pass a display name, the flow may fail even if the column is not required. Use the Get item action to retrieve the correct ID for the update.

Update Item Action vs Send an HTTP Request to SharePoint

Item	Update Item Action	Send an HTTP Request to SharePoint
Method used	POST or MERGE	PATCH (typically)
Required column enforcement	Enforced — all required columns must be supplied	Not enforced — only supply the columns you want to change
Error handling	Fails with 400/403 if required column is missing	Updates successfully even if required column is omitted
Use case	Simple updates where all required columns are known	Partial updates or when required columns change frequently

The Send an HTTP request to SharePoint action uses the SharePoint REST API directly. A PATCH request updates only the fields you include in the JSON body. SharePoint does not enforce required column validation on PATCH requests. This action is a reliable workaround when you cannot modify the required column setting or when you want to minimize flow complexity.

To use this action, configure the Site Address and Method as PATCH. In the Uri field, enter _api/web/lists/getbytitle('Your List Name')/items(Item ID). In the Headers, add IF-MATCH with value and Content-Type with value application/json;odata=verbose. In the Body, provide a JSON object with only the fields you want to change, for example: { "Title": "New Value" }.

Now you know why a required column blocks Power Automate updates and how to fix it. Start by checking the flow run history and comparing the action inputs to the list’s required columns. If you need to update only a few fields without supplying every required column, switch to the Send an HTTP request to SharePoint action with a PATCH method. This approach saves time and prevents future failures when required columns change.