Once your account or name list such as customer or supplier name had a transaction, you will not be able to enter the opening balances from the account or any name list profile window.
The only way to enter the opening balance is via a Make General Journal Entries or a transaction such as Invoice or Bill.
When you created transactions with an account or name, the Opening Balance field in the profile window will be closed. Hence, you cannot enter the opening balances by editing the account or name.
As for the item list, the opening balance field will be closed once the item name is being saved. The only way to enter the opening balances for the item is to enter via “Adjust Qty/Value on Hand” feature.
If you are not sure in General Journal (double entry), I suggest you prepare your opening balances before you start your company file.
I will try to create a new company file check list in my future blog. Do come back to my blog for an update.