「GA4 Bug」 Why is New Visitors 0?

Update time: April 16, 2025

Issue

Some people have encountered: New Visitors in GA4 is 0:

Reason

There is a bug in the User-provided data collection. Turning this function on will cause New Visitors to be 0.

The reason is that if you enable it, you will get an Effective User ID like @^+random numbers:
If you also use “Blended” or “Observed” for the ID used in the Reporting identityt, then New Visitors is 0.

Solution

One is to turn off “User-provided data collection”, the location is in GA4’s 「Admin」——「Property settings」——「Data collection and modification」——「Data collection」:

One is to select “Device-based” for Reporting identity.

Finally, just wait for the official fix.