Machine is leaking water externally dur...

This definitely solved the first part of my problem (where water was leaking beneath and to the side of the unit)....the small chamber that drains into the lower removable train was clogged with fine powered coffee. But, I believe there is also a seal probem between the white plastic value and the upper brew unit, as water leaks copiously during the pumping process. This likely requires replacing the plastic white valve with the new stainless steel valve referenced in another post.

Check the small chamber under the white plastic valve, behind the brew unit that might be blocked.