"Error Synchronizing" with Exchange on Windows Mobile 6.1

This is a strange one. If you are set-up to receive SharePoint notifications and you get one in your Inbox this seems to prevent Outlook on Windows Mobile from synchronising with the Exchange server. Very odd. More details here:

http://social.microsoft.com/Forums/en-US/windowsmobile/thread/2d887d3c-309e-4eae-a02f-7846ffba3b32/

No long term fix but if you delete the e-mail (you can delete on the handset) it will fix the problem and you will start to receive your e-mail again.