How to Debug ACF Fields Not Saving or Displaying in WordPress

ACF fields that fail to save or display correctly are a common WordPress development headache. Custom Field Finder helps by showing what is actually stored in the database, confirming whether the issue is a save problem or a retrieval problem.

Step 1: Is the Data Actually Saving?

The first question when a field is not displaying correctly is whether the data is being saved at all. With Custom Field Finder active, go to the post in the editor and look at the Custom Field Finder meta box at the bottom. Find the field key for your ACF field. Is the value showing what you expect?

If the value is there: the problem is in how you are retrieving it in the template, not in saving.

If the value is missing: the problem is in saving — check the field configuration, permission settings, and whether the field group is correctly assigned to this post type.

Understanding ACF Field Keys vs Field Names

ACF stores two related entries in post meta for each field:

• The field value, stored under the field name (e.g., my_field_name)
• A reference key stored under _my_field_name (with underscore prefix)

Custom Field Finder shows both. The underscore-prefixed entry is internal — it maps the field name to the ACF field key (which starts with “field_”). The actual value is in the non-prefixed entry. Use get_field(‘my_field_name’) to retrieve the value — never use get_post_meta() to retrieve ACF fields directly as it bypasses ACF formatting.

Diagnosing Save Failures

If the data is not saving, check these in order:

1. Field group assignment — Is the field group assigned to the correct post type and location rule? Go to ACF, then Field Groups, then edit the group and check Location Rules.
2. User permissions — Some ACF fields can be restricted by user role. Check the field settings for capability restrictions.
3. JavaScript errors — Complex ACF fields (repeaters, flexible content) require JavaScript to function. Open browser DevTools console and look for JS errors when saving.
4. PHP memory — Large repeater fields or flexible content with many rows can hit PHP memory limits during save. Check the PHP error log for memory errors.

Debugging Retrieval Issues

If the data is saved (visible in Custom Field Finder) but not displaying correctly:

<?php
// Use var_dump to inspect what get_field() returns
$value = get_field( 'my_field_name' );
var_dump( $value );
?>

Add this temporarily to your template to see the raw value. For relationship fields, image fields, and post object fields, get_field() returns an array or object rather than a string. If you are treating the return value as a string, it will not display correctly.

Checking the Correct Post ID

If get_field() returns null or false but the value is in the database, the post ID may be wrong. get_field() without a second argument uses the current post in the WordPress loop. Outside the loop, pass the post ID explicitly:

$value = get_field( 'my_field_name', $post_id );

Use Custom Field Finder on the specific post to confirm the field exists for that post ID before troubleshooting the template code.

Clearing ACF Caches

ACF caches field group data. After changing a field configuration, clear any object caches (Redis or Memcached if your host uses them) and reload the page. Persistent object caches can serve stale field configuration data after you make changes in the ACF field group editor.

For complex ACF implementations including custom field types, repeater fields with advanced logic, and ACF integration with WP All Import, a WordPress developer can debug and build the solution correctly.