When the Open existing model icon is clicked in the model window, Strand7 shows an Open File dialog for selecting the St7 file to be opened. You can navigate over your drives and other locations using this dialog, but the default (or initial) folder of the dialog will always be the folder in which the current Strand7 model is located. For example, if the full path of the model below is "C:\My St7 Files\Building.st7", clicking the Open existing model icon in that window will show the Open File dialog at "C:\My St7 Files", no matter what your last folder location was. If you have multiple Strand7 models open at the same time, the default location of the Open File dialog will depend on which icon you click (i.e., on which Strand7 window).
Open from the Startup Screen
If the Strand7 startup screen is showing, it means that no Strand7 files are currently open. In this case, the default folder location of the Open File dialog will be the folder in which the last Strand7 file was opened or saved.
Additional information
The Strand7 menu icon , available in both the model window and the startup screen, offers an item called Recent Folder. This provides a list of the most recent folders in which a Strand7 model was opened or saved. By clicking one of these recent folder items, Strand7 presents the Open File dialog with the default location being the selected recent folder.