Unfortunately, if the file didn't save properly and won't open, then you will have to start again.
FYI. TurboTax CD/Download has not generated *.ttbk backup files for several years. Only the *.ttxx file is created for a return.
Que sera, sera. Thanks for trying. The backup should be restored for the future.
I am not able to open the turbotax anymore after the upgrade. please help