If you want to fix the export location permanently, you can check the below options:
1. First, you have to update BUSY in the latest updated version. The latest version has given you the option to export any file to any location, so next time you do not need to set the same path again; it will pick your last exported path automatically, but it is not permanent; you can change it.
2. Also, you can create a new exe of BUSY and set its command line by giving the command /efp=path. It also sets your export location, but it is not permanent; you can change it.