DON'T save a file if Fruity acts strangely with a plugin, even if you remove the plugin and carry on - I lost a wicked track I'd spent about 8 hours getting together after adding a Buzz machine effect that was screwy. It threw up an error so I removed the offending machine and carried on trying other effects. Came to the end of the session and saved... next time I opened, file corrupt.. aaaaaarrrrrgghghhhhh

Rule number one, use the 'save as new version' option.