Quickmap seems to automatically know which layers to open, but what tells Quickmap which layers to open when you start Quickmap?

Answer: The database Qmap.mdb in the local data folder under qmap.exe (e.g. if you run C:\Qmap\Qmap.exe it will use C:\Qmap\Data\Qmap.mdb) tells Quickmap which layers to open, and where they are located.

More specifically the tables “QDefaultTable”, “QDataSource” and “QLayers” in Qmap.mdb are used, and the QDataSource table contains the location of the databases.

If any field the QSource column of table QDatasource contains [DEFAULTDIR] in any part of the string, Quickmap will replace this with the string value stored in the registry under HKEY_CLASSES_ROOT\Config\DataDir.