Will the system allow a “one-sided” or out of balance general journal adjusting entry to be made?

Will the system allow a “one-sided” or out of balance general journal adjusting entry to be made?

Yes. It will warn you that it is out of balance and ask you if you really meant to do it. It will allow you to complete the transaction though because a hardware malfunction or other reason could make it necessary to make an out of balance transaction. The system will give you a report of any out of balance transactions that have been entered as well.