Understanding the errAnonDistinctIdNonGUIDForm Error on $identify Event

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The error errAnonDistinctIdNonGUIDForm occurs when you're trying to use the $identify event with an $anon_id that doesn't conform to the UUID v4 format.According to the documentation, when using the Original ID Merge system, the $anon_id parameter in the $identify event must be in UUID v4 format: > "A distinct_id to merge with the $identified_id. The $anon_id must be UUID v4 format and not already merged to an $identified_id." Create IdentityThis error is specific to projects using the Original ID Merge system, as the documentation notes: > "The $identify event payload is only useful for projects using the Original ID Merge system; it has no functionality in other ID management systems." Create IdentityIf you're using Simplified ID Merge instead of Original ID Merge, you should be using the $device_id and $user_id properties rather than the $identify event. You can check which ID management system your project is using in your project settings.To fix this error, ensure that the $anon_id you're providing is in the UUID v4 format, which typically looks like: xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx where x is any hexadecimal digit and y is one of 8, 9, A, or B.

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The error errAnonDistinctIdAssignedAlready occurs when you're trying to use the $identify event with an $anon_id that has already been merged with another $identified_id in Mixpanel's Original ID Merge system.According to the documentation for the Create Identity endpoint, the $anon_id must not only be in UUID v4 format but also "not already merged to an $identified_id" Create Identity.This error specifically means that the anonymous ID you're trying to merge has already been associated with a different user ID in a previous $identify call. In the Original ID Merge system, once an anonymous ID has been merged with a user ID, it cannot be reassigned or merged with a different user ID.This is part of how Mixpanel's Original ID Merge system maintains identity clusters, where each anonymous ID can only belong to one identity cluster (limited to 500 distinct IDs per cluster) Migrating to Simplified ID Merge.If you're encountering this error, you may need to: 1. Use a different anonymous ID that hasn't been merged yet 2. Review your implementation to ensure you're not trying to reuse anonymous IDs across different users 3. Consider if your implementation might be calling $identify multiple times with the same anonymous ID but different user IDsRemember that this error is specific to the Original ID Merge system. If you're using or considering switching to the Simplified ID Merge system, the approach to identity management is completely different and uses $device_id and $user_id properties instead of the $identify event.

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