Why Unassigned Appears in GA4 Channels

According to the official documentation: 

Unassigned is the value Analytics uses when there are no other channel rules that match the event data

In fact, there are several situations as follows:

UTM parameters are not channel rules

UTM parameters are not channel rules, such as

• utm_source=Admin&utm_medium=Admin&urm_campaign=Admin
• utm_source=BLOG&utm_medium=ELLA
• utm_source=GA&utm_medium=AD_K

You can filter out unassigned , and then add “First user source/medium” in the secondary dimension

You can see that UTM is wrong, UTM should use Channel Rule, learn more: Understanding Default Channel Group in Google Analytics 4

Measurement Protocol is missing ga_session_id parameter

Send data through the MP  without the ga_session_id parameter, it will be classified as Unassigned

session_start is lost

When the session is opened, the session_start event will be sent, and the UTM information is on the session_start. If the session_start is not sent, the source/medium will not be set, and the channel will be Unassigned.

Total Sessions is 138, Unassigned Session is 5, which means session_start is 133, we can verify through events reports.

Note: Some sessions  have multiple session_starts, so if you extend the time range, you may encounter data inconsistencies.

Data is still being processed

If the data is still being processed and has not been processed, Unassigned will also appear.

Read more: If Google Analytics 4 Data Has Not Been Processed