I tried to export all the event in Excel format ... but the important information is missing ... no star azimuth or elevation are exported from OccultWatcher to Excel.
Are you talking about the "Export All Events to Excel" feature in the right-click menu? This only exports the columns which are displayed. You need to make sure you have "Star Altitude" selected in the "Choose Columns" setting (see attached image). When this is selected, the column will be displayed and also exported to Excel (actually CSV) format. Also note that the "Star Altitude" column contains both Altitude and Azimuth.