Okok as you know Exchange 2010 and 2013 has integrated the ability to archive mailboxes based on some policy (maybe later I'll write a post about it). But if you try to enable archiving on a mailbox just to test its functionality…. Well you could be waiting in front of the monitor for a long time….
This is because the archive is managed by an agent that is always active in background, but in reality, by default, it processes the mailboxes for archiving only between 1:00 AM and 9:00 AM which is also correct because it is always better adding load to the server during off-peak hours. The agent in question is the ManagedFolderAssistant and, in special cases, is however, always possible “awaken it” forcing the archive of a mailbox using this command:
Start-ManagedFolderAssistant -Identity username
There is also another command that can be useful to define how often the agent needs to do its job:
Set-MailboxServer MyMailboxServer -ManagedFolderWorkCycle 1
In this way I specify that the agent must check the mailboxes once a day, I refer you to the official help page for the parameters that can be passed to the cmdlet, you can specify days, hours, minutes and seconds (obviously the more often it works the more it weighs down your server):