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
So these projects work for a few days, and then problems appear, right?
Please attach a test project with which you can repeat the problem, here or in the forum PM.
