Upgraded to photoshop Elements 15 can't save scrapbook files anymore

Hi,

I have been searching for this answer and can't seem to find it anywhere.  I had previously used Photoshop Elements 10 for all of my photo editing and digital Scrapbooking.  I recently upgraded to Elements 15 and have found I can no longer save files that I was once able to save in Elements 10.  Some of my digital scrapbook pages have lots of layers and this was NEVER a problem before to save, it is saying my files are now over 2GB and for 7 years this has never been an issue in any other version of Elements I have owned. How can I fix this?  I need to be able to save as a PSD so I can edit later if I need to.