Are you trying to open a project with the xml extension in BAS? Probably your project is damaged, you did not edit it manually using text editors? Try to restore it from backups located here:
C:\Users\User\AppData\Roaming\BrowserAutomationStudio\projectbackups
Use RESET option in BROWSER TAB . this will clear cookies but cache will be still present. You can also make a profile and save it for further use. Let us know if this works for you.
