I have followed a number of the suggestions above and am working on my local drive but am still experiencing file corruption issues. The latest file to corrupt, I managed include the page in a new publisher file and found that a couple of the images, whilst they appeared in the layers tabs, were black. So I am assuming this is the problems when the file is saved. All the images are 'embedded' rather than linked so I would have thought the save process would have stored them all within the designer file.
Although I could see the designer file content when I open and added a new page in publisher, I could not save the publisher file. Even after removing the images that were black, it still wouldn't allow me to save so couldn't recover the file.
To get round this for now, I have various version of the file saved (as suggested) which seem fine (at the moment) but then for no apparent reason they are flagged as corrupted when I try to open them again.
Could it be the file size because there are multiple layers with images in? Is there any mileage in me changing the images to 'Linked' and have a dedicated folder for the included images? I don't really want to go through each file and change them if overall file size is not the issue!!
Thoughts gratefully received.
Thanks