Mailbox searches not starting

Hi,

When i create a new mailbox search using the following command the status of the search stays at 'NotStarted' and I can't figure out how to trigger the search to begin.

New-MailboxSearch <Search Name> -SourceMailbox <Source Mailbox> -TargetMailbox <Discovery Mailbox> -LogLevel Basic -IncludeUnsearchableItems

Thanks for you help