No special stock allowed

What causes this issue?

In Aerospace & Defense subcontracting scenarios it is not allowed to
have a special stock without an account assignment, therefore all A
&D special stock relevant data is reset.

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?

If you want to use a special stock you may enter an PM/CS order, a
project, or a sales order as an account assignment object.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.