I can use sandboxie to run Steam Twice without a conflict. Yet when I try to run some other programs they will not open twice because they can detect the program running in Sandboxie. How? I thought the whole point of sandboxie was to isolate it?
Maybe you find this thread helpful. Sandboxed processes are not hidden from the host. The host can see what processes are running. By default, processes inside a sandbox can see the processes on the host, but they can not interact with them, e.g. not terminate them or read their memory. This can be changed by setting HideNonSystemProcesses=y