Deletion not possible (master data).

What causes this issue?

You want to delete controlling area &V1&. This is not possible because
master data was already created for controlling area &V1&.
&V2&: &V3&

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?

Delete all master data in controlling area &V1&. Only then will you be
able to delete the controlling area.

Error message extract from SAP system. Copyright SAP SE.