Try deleting the gray pages and add new ones to replace them, then export to IDML.
After your file is recovered, you should install your updates, if you haven't already done so.
Try creating a new document with the same page size and margins.
In the troubled document use the Layout>Pages>Move Pages
Select all pages - and choose the destination to be your new document.
If you can move all your pages - see if you can export/save that document.
Thank you this worked out perfectly! I did do an update as well to be safe but the Layout>Pages>Move Pages to a new document did the trick. Very much appreciated.