Processing terminated; summarization error

What causes this issue?

A serious error occurred during data summarization.

System Response

Processing is terminated.

How to fix this error?

Notify SAP of the problem, specifying the following:
Start transaction (drilldown reporting, query)
In the case of drilldown reporting:
Name of the drilldown report
Name of the report type
In the case of a query:
Name of the query
Name of the user group
Name of the variant

Procedure for System Administrators

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

Error message extract from SAP system. Copyright SAP SE.