Have posted entries to a prior year in period 12, but they are not closing to the Retained Earnings account.
The ability to post to a prior year that has already been closed to Retained Earnings is a valuable function. In GL Setup / Options, this function is turned on from the Posting tab:
In order for the prior year posting to be successful, however, the required period must be unlocked in the fiscal calendar, or the setting for locked periods in the Company Profile must be set to 'warning' or 'none'. If the Locked Fiscal Period setting is set to 'Error', than the fiscal calendar MUST be unlocked for the specific period.
When an entry is created for a prior year, a closing entry is automatically created for any line items that reference an income statement account when the entry is posted. For example, if the following entry is posted to a prior year in period 12:
DR Accrued Accounts Receivables $10,000
CR Revenue $10,000
Then the following entry is automatically created and posted:
DR Revenue $10,000
CR Retained Earnings $10,000
However, the closing entry is not posted into period 12, with the original journal entry - but rather is posted to period CLS (period 15).
The closing entry can be seen in the printed posting journal, or in the account activity for the RE account for period CLS.