(not set) is a placeholder name that Analytics uses when it hasn't received any information for a dimension. The reasons (not set) appears as a dimension value in a report vary depending on the dimension. While standard reports display a default set of dimensions, you can customize many of them to change the dimensions they display.In this article:
Google Ads dimensions
If you see (not set) as a dimension in your Advertising reports, check for these common causes:
Google Ads account and Analytics property are not linked
Check if Google Ads and Analytics are linked and fix it if they are not.
Auto-tagging is not enabled
Traffic from unlinked Google Ads accounts
If the GCLID parameter remains attached to your Google Ads final URLs, check if there are any other Google Ads accounts advertising your website that are not linked to your GA4 account. Traffic from unlinked Google Ads accounts will appear as (not set) in the Google Ads reports because it's not possible to map these conversion events to a particular click.
Manually tagged destination URLs with incomplete or incorrect UTM parameters
If you manually tag destination URLs with UTM parameters instead of using auto-tagging, (not set) can appear for URLs with incomplete or incorrect parameters. These URLs can stem not only from Google Ads accounts, but from any other source such as social networks, blogs, or other websites. When Analytics doesn't receive the necessary parameters to identify where traffic from manually tagged URLs comes from, (not set) appears.
Session source / medium dimension
Session source / medium will report (not set) for sessions where the automatically collected event
session_start is missing.
Landing page dimension
(not set) can appear for the landing page dimension when a session doesn't have a
Content group dimension
If you combine the content group dimension with automatically collected events such as
first_visit, the content group dimension can appear as (not set). That is because automatically collected events don't accept the
content_group parameter. Thus, there is no valid data for this combination.
(not set) can also appear when your event sends the
content_group parameter but it is an empty value, for example
Custom defined User ID dimension
Generally, it is recommended that you do not register a user ID as a custom dimension. If you use a custom defined User ID dimension, (not set) can appear.
Learn more about best practices for User-ID.
For an event with custom parameters, you may see (not set) as a parameter value during the first 24 hours after you register a custom parameter. Check that it's been more than 24 hours since creation. Once the initial 24-hour period has passed, you should see the expected parameter values.
If you try to send a custom parameter with the automatically collected events
first_visit, the parameter will appear as (not set). The
first_visit events can only be sent along with the following default parameters: