Summarization data is blocked by user &1.

What causes this issue?

The summarization data that belongs to: summarization version &V2&,
investment program &V3& and logical system &V4&, is currently blocked
by user &V1&.

System Response

Processing is terminated.

How to fix this error?

Try again when user &V1& has stopped working with the data.

Error message extract from SAP system. Copyright SAP SE.