This message: https://www.wilderssecurity.com/threads/sandboxie-plus-0-9-0.439305/page-2#post-3022811 make me to believe there is a bug in Sandboxie related to context menus. Context menu is a key in the registry. A key used by BSA to check for Sandboxie's presence. If the key is not present BSA will consider Sandboxie is not installed in the system. So let's wait until David fixes that bug and then check again, please.