Some strange stuff in Cubase 8

Hey guys!

I’d really like some help on how to solve a few issues I’m dealing with.

First of all - I’m having problems with latency while recording.
I’m using a Mac Book Pro 15" and my audio hardware is a UAD Apollo Twin Duo.
Shouldn’t be a problem, but it is.
I’ve tried to change the buffer sice up and down… don’t really know what else to do?

Another problem is that since upgrading to Cubase 8 - for some reason a few pop-up windows won’t open more than once.
Importing audio for instance - or loading a track channel preset.
Once - I get this to work when in an open session, then the windows just won’t open the next time I wanna import and browse my sample folders for sounds. EXTREMELY annoying.

I’m using Yosemite - and I’m worried it might have to do with that too, but the pop-up window issue definitely was working on Yosemite and Cubase 7.5, so something’s up.

Last but not least - Cubase have never crashed on me before (at least not noticeably amounts of times) - but, again, since installing Cubase 8, it happens a LOT. What is this all about?

Appreciate your help with this if you have any.