Due to a problem in the Quartus® II software version 11.0, if you restore a Quartus II Archive (.qar) file by selecting Restore Archived Project on the Project menu, the Restore Archived Project dialog box does not select the correct default destination folder automatically. The correct default destination folder should be <Quartus II Archive name>_restored.
To work around this problem, click Default Destination Folder after selecting a .qar. Alternatively, restore a .qar file by selecting Open Project on the File menu or by double-clicking the icon for the .qar in your file browser.
This problem is scheduled to be fixed in a future version of the Quartus II software.