Unfortunately, there is no way to “undo” a Close Year in MultiLedger; once you’ve closed the year, you cannot go back. Hopefully, you have a recent backup that you can restore and work forward to get back to where you were before closing the year.
In MultiLedger version 7.0 & higher, the program requires a backup to be saved before the Close Year command was completed. Restore this backup to the desired location and continue working. For more information about restoring a backup file, see your User’s Manual.