I have tried to copy a *.desktop file from /usr/share/applications to my desktop and changed the issue "Allow the applikation to start up" to true and the permissions to "none", but no app want start after I click double onto it.
Did you place the copied file in /.local/share/applications?
Did you assign in Permissions by Right click > Permissions?
If you copied a system .desktop file that is located in Root; it may need sudo permissions to execute launching of the application - which still has its program files in Root even if you moved its .desktop Identification File.