Please provide us with such information to investigate your problem in more details: What build of Parallels do you have? For Mac :You can check it in Parallels desktop menu (on top of the screen) - About Parallels desktop For PC : Go to Parallels folder (By default, C:/Program Files/Parallels? parallels Workstation) - right-click on Image tools - Properties. Select Version tab. What type of .hdd file do you have (expanding/plain)? What error exactly do you have? Please describe the full sequence of actions that lead to this error. How much free space do you have on Host OS?