i´ve NOT used GP3 over a couple of weeks ( to hot in summer in my appartment),
and now that i wanted to test a VST that i have was i NOT able to play it.
I´m in fact not able to play any of my old gigs.
i loaded several ones. Can´t play one.
i have also NO midi input shown in the midi monitor.
( final sum up: it has to be a midi problem)
my masterkeyboard ( SL88 Grand) is connected to the PC ( macmini) and i can play Pianoteq in standalone.
when i open the midi settings in GP3 is there a couriosity:
where my midi devices ( incl. the SL88) are listed, can i NOT deselect (or select) any of the check boxes. IMHO, do they also look different than expected.
A tiny bit less bright, like set back a bit.
Things get wilder:
i powered my Midi controllers on ( 2x Novation Launch Control XL + a smaller one)
and i can play widgets when i check.
But no midi activity is shown in the midi monitor.
as audio interface is the right one shown,
ok, i get audio out when i load “Granite” ( a granular sampler that plays a sample in loop)
but i can´t get any Sound out of any on my patches.
These all are dependent on the midi input of the keyboard.
So my problem IS the midi connection vs. GP3
what can i do to debug that situation ?
( what has changed since i played with GP3 the last time ?
i updated the arturia plugins, and i installed the “Exponential Audio” reverbs/FX i got in a package, 2-3 plugins)
long post, sorry / any help MUCH asppreciated 
), not always, that’s what makes the whole stuff so funny on Windows 