If a file is truly corrupted it cannot be recovered. However, if you have automatic backup enabled, SYNCHRO saves a copy of the SP file every time you open a file which you can return to if there is a problem with the file you were working on.
To check whether this was enabled and where the files are located, go to Options>General>Auto Save. It is highly recommended to always enable Auto Save Project and Backup project file when opened. If it was previously enabled, backup copies of the file can be found in the Auto save and backup file location