When copying any file from a CD to a Windows hard drive, the file remains in a read only state. 4D gives no alert when opening a data file that is read only due to requests from developers. This allows a 4D database to be run from a CD as a demonstration without disturbing the user with warning messages. Even if the read only state of the data file is changed while the structure is running, 4D will still consider the application to be in the same state as it was when it was opened. It will store the changes in memory until 4D is quit upon which time the cache cannot be flushed (due to the read only file) and any changes evaporate into the great cyber twilight zone.