Please try saving the file to a different location on your hard drive or with a different name. You can do this by choosing File> Save As from the top left corner.
You can also try renaming the .ttbk file to .tt18 – the .ttbk is the backup file, and it may have save the changes you made to your file.
Also, if you installed the software from the CD, to prevent further issues, you should uninstall it and then use the download from our website to reinstall the software. You can download TurboTax from here: https://turbotax.community.intuit.ca/replies/3001486