The "Negative quantities allowed" indicator will be set automatically

What causes this issue?

You want to run the period closing program and have chosen the option
allowing negative values for the current previous period, that is, for
the period that is the previous period before period closing.

System Response

The system therefore automatically selects the option allowing negative
quantities for the current previous period too.
Note
Negative stock values can arise only if materials also exist that have
negative stocks.

How to fix this error?

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.