When performing an SAP system refresh, the source of SAP instances will be visible at the transaction code ST06. Therefore, all these old or inactive SAP instances are no longer required, and you can remove them permanently.
So, how do you clean this?
Open the transaction code RZ21. Then, scroll down and click Display Overview under Topology and System Overview.
Jump to the Local Segment tab and switch to edit mode.
Identify the inactive SAP instances (the segment status will show status as shutdown).
Proceed with the deletions.
Once done, you can re-open transaction code ST06 and see the reflected changes.
