Well, I dont think I have ever had poseidon crash on me, but then I have been told that Poseidon conflicts with some other programs - WHDload is a main example.
Nope, sorry to correct you here. It's not Poseidon which is the bad guy.
Poseidon uses interrupts to communicate with the USB host controller. If another software package takes over the machine (like WHDload does, by disabling multitasking), interrupts will still be there (as WHDload doesn't know how to deactivate the USB ints) and will freeze your machine, as the USB int server will never be activated again.
Something similar will happen with other software which may use a buggy interrupt server (remember, Amiga uses daisy chaining with interrupt servers, so if one server closes the chain too early by mistake, you are done).
The best way to get around this is (like already proposed) to use a small utility checking the mouse buttons on startup, and changing the startup-sequence accordingly.
Michael
Michael