Local migration batch hangs on 'syncing'

I create a migration batch for one user to move from one mailbox database to a different one. All servers Exchange 2013 build 712.24.
The current and the target mailbox database are in a DAG. The migration batch hangs on 'syncing' and nothing happens. All database in DAG are fine (healthy and content index healthy). Nothing helpful in application logs" migration statistics with report show

[ExchSvr2013] Job resumed with status 'Queued'.
[ExchSvr2013] Relinquishing job.

ExchSvr2013 is the server with the active copy of the target database.

The only other thing I see is this from the migration statistics:

PercentComplete                        : 0
CompletedRequestAgeLimit               : 7.00:00:00
PositionInQueue                        : 1/1 (Position/Queue Length)
InternalFlags                          : WordBreak

I did apply http://support.microsoft.com/kb/2807668 (ContentSubmitters)

I did restart MS Exchange Replication and Search service.

Since I have no further error information I would ask for some advise how to troubleshoot the issue.

Gerhard Waterkamp ACSLA Inc.