The system settings do not allow changes to be made to object &1 &2

What causes this issue?

Settings for the system and namespace editability of this SAP System do
not permit changes to object &V1& &V2&.

System Response

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

How to fix this error?

Processing is terminated, object &V1& &V2& is not generated.

Procedure for System Administrators

Settings for editability are made using Transport Organizer
Tools (Transaction <DS:TRAN.SE03>SE03</>). Expand the administration
node, and execute the 'Set system editability' program. The possible
settings are described there.

Error message extract from SAP system. Copyright SAP SE.