As being discussed in thread.

I had a question is there a way to force a true fresh install of bm3.9,
one that would overwrite any existing BM settings in edir? Or a way to
remove the existing appearently corrupt settings prior to installing
bm3.9? so a fresh install can take place.

As I posted in the thread I tried a fresh install and I came up with the
same proxy failure.

I have a second server and have backed up my ACL list so to remake the
proxy settings would be rather easy for me, the biggest pain would be
rebuilding the non-cachable list, which is on my second BM server so
easily attainable.