We have found a bug with a text item in X7 that works fine in X5. Here's the sample 18KB .des file? test Outsides4.des
Here's feedback from the tech team: The issue is caused by the nested text that has been embedded as a graphic in the text.
Attached you find a version of the file with an updated element that does not produce any error when saving / editing.
test Outsides4_X7.des
Steps to fix a file like this (as a workaround when you come across that issue in old files you open and edit with X7):
...you should now be able to work with that file in Corel DESIGNER X7 (and CorelDRAW X7) without any further issue.