Why GA4 Shows 'Unassigned' for utm_source (The Orphaned Parameter Fix)

You spent 20 minutes carefully crafting UTM parameters for your email campaign.

You added utm_source=newsletter to every link.

You sent it to 15,000 subscribers.

GA4 shows the traffic as "(direct) / (none)" or "Unassigned".

Your email campaign just disappeared into the void.

Here's the problem: utm_source without utm_medium is like a letter without an address. GA4 receives it but has nowhere to put it.

This is called an "orphaned parameter," and it's the #1 reason perfectly tagged campaigns show as unattributed traffic.

What is an Orphaned utm_source?

Orphaned parameter = utm_source present but utm_medium missing

Your URL looks like this:

yoursite.com?utm_source=newsletter&utm_campaign=spring-sale

Notice what's missing? utm_medium

GA4 requires BOTH utm_source AND utm_medium to attribute traffic correctly.

If you only send utm_source, GA4:

1. Receives the parameter
2. Sees utm_medium is missing
3. Can't determine channel grouping
4. Routes traffic to "Unassigned" or "(direct) / (none)"

Your utm_source becomes orphaned—present but unused.

Why GA4 Requires Both Parameters

GA4's attribution logic follows this hierarchy:

First check: Platform click IDs (gclid, fbclid, etc.) Second check: utm_source + utm_medium combination Third check: HTTP referrer Last resort: "(direct) / (none)"

When you only provide utm_source:

• GA4 can't use it (needs utm_medium too)
• Falls through to checking HTTP referrer
• Email has no referrer (direct click from inbox)
• Result: Classified as "(direct) / (none)"

The utm_source you added is completely ignored.

Real Example: $42,000 Email Campaign Lost

Client: B2B SaaS company Campaign: Product launch email to 28,000 leads Email spend: $4,200 (design, copywriting, list maintenance)

URLs used in email:

https://productsite.com/launch?utm_source=email&utm_campaign=launch-2024

What they expected in GA4:

• Source: email
• Medium: email
• Sessions: ~2,800 (10% open rate × 50% click rate)

What GA4 actually showed:

• Source / Medium: "(direct) / (none)"
• Sessions attributed to email: 0
• Sessions in "Unassigned": 2,847

The impact:

• CMO thought email generated zero traffic
• Proposed cutting email budget by 60%
• Attributed 2,847 sessions to "organic interest" instead
• Nearly killed a channel producing $42K in pipeline

What was actually happening:

• All 2,847 sessions WERE from email
• utm_source=email was present but orphaned
• Missing utm_medium caused GA4 to reject attribution
• Traffic dumped into "(direct) / (none)"

The fix: Added utm_medium=email to all links. Next campaign tracked perfectly.

How to Check If You Have Orphaned Parameters

Quick URL Test (10 seconds)

Look at your campaign URLs. Check for this pattern:

❌ Orphaned (missing utm_medium):

?utm_source=newsletter
?utm_source=newsletter&utm_campaign=spring
?utm_source=facebook&utm_campaign=spring&utm_content=video

✅ Complete (has utm_medium):

?utm_source=newsletter&utm_medium=email
?utm_source=newsletter&utm_medium=email&utm_campaign=spring
?utm_source=facebook&utm_medium=social&utm_campaign=spring&utm_content=video

GA4 Traffic Report Test (2 minutes)

1. GA4 → Reports → Traffic Acquisition
2. Look for "(direct) / (none)" or "Unassigned"
3. Click on the row
4. Add secondary dimension: "Session source"
5. Check if sources appear with "(none)" medium

If you see actual source names with "(none)" medium → You have orphaned utm_source parameters.

Examples:

• newsletter / (none)
• facebook / (none)
• partner-site / (none)

These should never exist. Every source needs a medium.

GA4 Realtime Test (30 seconds)

1. Create test URL: yoursite.com?utm_source=test
2. Click it in incognito browser
3. GA4 → Realtime report
4. Check traffic source

If it shows as "(direct)" → Confirmed orphaned parameter issue.

The 2-Minute Fix

Fix 1: Add utm_medium to All Links

Before (orphaned):

https://yoursite.com/page?utm_source=newsletter&utm_campaign=spring-sale

After (complete):

https://yoursite.com/page?utm_source=newsletter&utm_medium=email&utm_campaign=spring-sale

Common utm_medium values by channel:

• Email: utm_medium=email
• Organic social: utm_medium=social
• Paid social: utm_medium=paid-social or utm_medium=cpc
• Partner links: utm_medium=referral
• Display ads: utm_medium=display
• Affiliate: utm_medium=affiliate

Fix 2: Bulk Update Existing Campaigns

For email marketing platforms (Mailchimp, Klaviyo, etc.):

1. Find default UTM settings
2. Check if utm_medium is configured
3. Add default: utm_medium=email
4. Apply to all templates

For social scheduling tools (Buffer, Hootsuite, etc.):

1. Check UTM builder settings
2. Ensure utm_medium is always included
3. Set default based on platform (social, paid-social)

For link shorteners (Bitly, etc.):

1. Review campaign builder defaults
2. Verify both utm_source AND utm_medium are required fields
3. Don't allow links to save without utm_medium

Fix 3: Update UTM Templates

If you use a UTM template or builder:

Minimum required parameters:

utm_source=`{"{"}{"{"}source{"}"}{"}"}}`     ← REQUIRED
utm_medium=`{"{"}{"{"}medium{"}"}{"}"}}`     ← REQUIRED
utm_campaign=`{"{"}{"{"}campaign{"}"}{"}"}}` ← RECOMMENDED

Never create URLs with only:

utm_source=`{"{"}{"{"}source{"}"}{"}"}}`     ← INCOMPLETE
utm_campaign=`{"{"}{"{"}campaign{"}"}{"}"}}` ← INCOMPLETE

Why This Mistake Happens

Reason 1: Confusing utm_source as "Enough"

Many marketers think: "If I add utm_source, GA4 will know where traffic came from."

Wrong. GA4 uses source + medium together to determine channel grouping.

Source alone is ambiguous:

• utm_source=facebook → Organic post? Paid ad? Shared link?
• utm_source=google → Organic search? Paid search? Display ad?

Medium provides context:

• utm_source=facebook&utm_medium=social → Organic post
• utm_source=facebook&utm_medium=cpc → Paid ad
• utm_source=google&utm_medium=organic → Search result
• utm_source=google&utm_medium=cpc → Google Ad

Reason 2: Outdated UTM Guides

Some older guides say: "Add utm_source to track traffic sources."

They don't mention that utm_medium is equally required.

This advice worked in Universal Analytics (old GA). It doesn't work in GA4.

Reason 3: UTM Builders with Poor Validation

Some UTM builder tools allow you to create URLs without utm_medium.

They should flag this as an error. Instead, they let you generate broken URLs.

Reason 4: Copy-Paste Errors

You copy a URL from a previous campaign:

yoursite.com?utm_source=newsletter&utm_medium=email&utm_campaign=april

You update it for the new campaign:

yoursite.com?utm_source=newsletter&utm_campaign=may

You accidentally deleted utm_medium during editing.

What About utm_campaign?

utm_campaign is optional for attribution but highly recommended.

GA4 can attribute traffic with just utm_source + utm_medium:

?utm_source=newsletter&utm_medium=email

This will show correctly as: newsletter / email

However, you won't be able to:

• Distinguish between campaigns from the same source
• Track performance across different email sends
• Report ROI per campaign

Best practice: Always include all three:

?utm_source=newsletter&utm_medium=email&utm_campaign=spring-sale

FAQ

Can I use just utm_medium without utm_source?

No. GA4 requires BOTH utm_source AND utm_medium. Using only utm_medium creates the same orphaned parameter problem.

Will fixing this restore historical data?

No. Historical data remains as "(direct) / (none)". The fix only works for new sessions going forward. Consider annotating in GA4 when you fixed it.

What if I see "Unassigned" traffic but my URLs have both parameters?

Check these other causes:

1. Double encoding: utm_source=newsletter became utm%5Fsource=newsletter
2. Parameter order issues: Some platforms break if utm_source isn't first
3. JavaScript stripping: Your site's code may be removing parameters
4. Fragment before query: #section?utm_source=... (should be ?utm_source=...#section)

Can I use custom medium values?

Yes, but use GA4's standard channel grouping values when possible:

• organic, cpc, referral, email, affiliate, display, social, video, audio, sms, push

Custom values (like "newsletter" or "partner") work but may not map to GA4's default channel groups.

Does this affect Google Ads auto-tagging?

No. Google Ads uses gclid, which doesn't require utm_medium. This issue only affects manual UTM parameters.

Prevention Checklist

✅ Setup (one-time):

• Document: "utm_source AND utm_medium are both required"
• Update all UTM templates to include both parameters
• Configure email platform with default utm_medium=email
• Set up validation in UTM builder tools

✅ Before Every Campaign:

• Verify utm_source is present
• Verify utm_medium is present
• Test URL in incognito → Check GA4 Realtime
• Confirm traffic shows correct source/medium (not "(direct)")

✅ Monthly Audit:

• GA4 → Traffic Acquisition report
• Filter to "(direct) / (none)" or "Unassigned"
• Add secondary dimension: "Session source"
• Investigate any sources showing with "(none)" medium
• Find and fix campaign URLs missing utm_medium

Conclusion

Seeing "Unassigned" or "(direct) / (none)" traffic when you added utm_source?

You have orphaned parameters.

The fix:

1. Add utm_medium to every URL with utm_source
2. Use standard values: email, social, cpc, referral, display
3. Test URLs before sending campaigns
4. Configure defaults in email/social tools

utm_source without utm_medium is worthless. Always use both.

This 2-minute fix ensures every campaign you tag actually shows up in GA4 reports.

Related: UTM Parameter Requirements Documentation