You can only post goods receipt for the whole HU

What causes this issue?

You have attempted to post a partial goods receipt that contains items
of a HU, but which does not contain all the items belonging to the HU
with the highest hierarchy level.

System Response

The system does not permit such partial postings.

How to fix this error?

Post the handling unit as a complete goods receipt.

Procedure for System Administrators

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

Error message extract from SAP system. Copyright SAP SE.