AngeliaSync is both an intuitive interactive desktop application and a flexible automation tool. When you run AngeliaSync by clicking its desktop icon (not to be confused with a shortcut that you may have created in the Profile or Profile Groups form), the application is said to be in "Interactive Mode". In this mode, AngeliaSync is configured to add, modify, or delete Profiles and Profile Groups in the Configuration Database - and as such, it requires exclusive "write" access to that database. This means that only one instance of AngeliaSync can be executing in Interactive Mode at any time. However, any number of instances may be running simultaneously in "Automation Mode".
AngeliaSync is said to be operating in "Automation Mode" whenever it receives its operating configuration from the command line, regardless of whether this command line is executed via desktop shortcut or in a command window or batch file. In Automation Mode, the Configuration Database is never modified so any number of instances of AngeliaSync can execute at the same time, and can execute even if an "Interactive Mode" instance is also present.
If you attempt to run AngeliaSync in Interactive Mode while another instance is still active, you will receive a "Configuration file is locked - Please re-try later." error dialog. The application will terminate when you acknowledge the dialog - and will have not effect on any other instances of AngeliaSync that may be running.