Cubase 8 LE with Overbridge but the A4 does not start

OK, so here is the description of my problem:

I run Cubase 8 LE on a MacBook with OSX 10.11
The latest OverbridgeVersion is connected to my A4
I fed a modular synth into my OT and the OT enters
the external in of the A4 (and is synced via Midiports
with the A4)

Everything works with Cubase 6 LE, no problem. But
with 8 LE the GUI of Overbridge shows no sign of
anything strange but when I start Cubase the A4 and
of course the OT do not start.

Somewhere along the way Overbridge said that I should
unlook the ASIOguard but I have no clue what and where
I do find that.

Last little extra that again is no problem with Cubase 6 LE
is the fact that I run a Nektar IMPACT LX 25 as well…

I could run my live set up with Cubase 6 LE but realy like
to check out the 8 LE version.

Any hint/help is welcome.