I have had this problem for a few years now and I cannot seem to find a fix for it.
More and more it becomes an annoyance for my co-workers and I thought I would throw the question in here once again.
I am having a problem where files saved in excel 2003 format by an Win7/Excel2007 client to a Terrastation server (irrelavant as it happens on 2k3 server also), failes to synchronise and ALWAYS ends up OFFLINE.
Even simply opening the .xls in Excel 2007 renders the file offline.
A manual sync is then required for the rest of the office to see the file on the server.
This does NOT happen to Excel 2007 format files saved to the same location using the same machine.
I think a longer explanation is here: http://forums.techarena.in/vista-help/887452.htm
I didn't have this problem with XP Pro/Office 2003, but I have had the same problem with Vista/Office 2007.
Something tells me that the way Excel 2007 saves the 2003 format file is stopping sync center from allowing it to sync.
I can performa manual sync and it goes back online (until you open it in Excel 2007 again)
Can someone PLEASE help. This issue has been a problem in my network for ages, and I thought upgrading to 2010 would fix it, but it hasn't.