Go into Period End and close the months one at a time. 

If I have a bunch of months to close in GL here is what I usually do. 

All of this presumes you have already printed any necessary reports and agreed subsidiary ledgers to control accounts. It is not a bad idea to also have a backup prior to closing in case anything goes wrong. 

1. First - go into GL - Setup - GL Options and be sure you are retaining the maximum amount of history. You can always purge - but you'll never get that history back. And my experience is that many people regret purging history.

2. Then I go into GL Options and set the period to 12 and the year to whatever year I want to close. I have not found that skipping years has been a problem however I would gladly be corrected if someone were to say my process was wrong.

In my experience general ledger is one of the more 'bulletproof" modules for closing. If you find an issue with any totals you can always recalculate account balances from the general ledger utilities menu.