But do you have an auto-backup configured? It is located at Tools->options -> (workspace) -> Save. You can set the elapsed time between backups (eg 10 minutes) as well as the destination folder. If you actually have it set you could look in the destination folder and see if there is a backup there. If not, consider setting it up for future use. You can also set it to make a backup upon saving the file.
There is something corrupted with the file as it has been saved that Corel won't open it. Maybe there is a chance that another software that can import CorelDraw files might overlook the glitch and try to import the rest. Depends on what part of the file is corrupted.
See it here: http://www.computing.net/answers/office/how-to-view-cdr-file/19676.html
If instrument above didn't help, you would need to identify what may have caused the file corruption. Possible causes could include:
- Document was corrupted / not saved due to the program crashing or hanging
- Saving large files to a network drive.