Wondering why GA4 shows “(not set)” or “(unassigned)”? This free cheat sheet from Hedgehog Marketing lists every common cause and how to fix it - from broken UTMs to cookie restrictions.
Use this Common Causes Cheat Sheet to quickly identify why your GA4 data shows “(not set)” or “(unassigned)” - and what to do about it.
Each issue includes a clear fix or action step so you can resolve data gaps fast.
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Keep it beside your troubleshooting checklist for a complete GA4 data recovery toolkit.
A reference card for diagnosing common GA4 data anomalies - why sessions spike, why conversions drop, why "(not set)" appears, why traffic sources look wrong, and what each symptom typically indicates. Keep it open when reviewing your analytics data and something doesn't look right.
"Direct" traffic spikes: usually means UTM tagging broke on a campaign - traffic that should be attributed to email or paid social is landing as Direct because the UTM parameters were stripped or missing. Sudden conversion drop: before investigating ad performance, check whether the conversion event is still firing. A website update or GTM change is often the culprit. "(not set)" in session source: often caused by server-side redirects stripping UTM parameters, or by events firing before GA4 has recorded the session source. Bounce rate of 0% or 100%: GA4 calculates bounce rate differently to Universal Analytics - 0% means engagement rate is 100%, which isn't realistic and usually indicates a misconfigured engagement threshold.
(1) Is conversion tracking still firing? Check GTM Preview on the conversion page. (2) Did anything change on the website in the past 48 hours? A template change, plugin update, or GTM publish can break tracking. (3) Is the date range including the GA4 processing lag? Data from the last 24–48 hours may be incomplete.