Yes. I am manually creating the virtual drive folder (%drive_c%), and i put in there the ##Attributes.ini file with DirectoryIsolationMode set to WriteCopy or Full. But there is now difference. I am able to write to the root of the directory and the changes are not saved in my sandbox but on the physical drive. If i create a new folder and a file in that folder, the folder and the file are saved in my sandbox. A just can understand this behaviour. It is like that for the root of the C:\ Drive the DirecotryIsolationMode is set to Merged, and for the other directories it is set to WriteCopy.