Core Data app saving zero length files

FROM : Simon Fell
DATE : Fri Nov 02 06:01:40 2007

Hi,

I have a core data document based app that i wrote on Tiger, since 
moving to Leopard I've noticed that if I open an existing document, 
make no changes, and then save it, it saves a zero length file only, 
all the data is gone. If you make some changes to the document between 
open and save, then everything appears fine. (I'm using the XML store)

I've rebuilt the app on Leopard, and it made no difference. I'm going 
to start digging through it, but has anyone seen anything similar? 
seems like it could be a serious issue.

Thanks
Simon