Also, for what it's worth, just in case there is an issue of clean installs:
My Mac Pro was delivered with OSX 10.10.2 and I updated it to 10.10.3 as almost the first thing I did.
I then went directly for Virus 5.1.1.0, so I had no intermediate versions on there.
My MacBook Pro is 2011 vintage, so has been through several OSX versions and Virus versions.
I've had MIDI crashes on my Mac Pro (from Marc's analysis of the logs), but no problems on my MacBook Pro.
not quite, CFRelease has a 'trap' when passed a null pointer, so, probably caused by an 'optional' resource being released when not allocated, or a double release (possibly by a code being called back from 2 handlers)... but still simple to fix
(pity the driver code is not open source :))
MIPS also traps NULL pointer access and control is passed to an installed handler.
I know we're getting a bit off-topic, but...
The methods for a pointer incorrectly becoming NULL are many and varied. As you say - over release/free on multiple instance resources, or a multi-threading ordering issue in allocating / freeing. I've seen people really tie themselves up in knots on C++ systems which don't keep proper track of their resources. Multi-threaded systems which don't properly protect the resource whilst it's deconstructed can also result in confusion. Critical section / mutex / semaphore protection is often not implemented well - at least on the systems I've worked on.
...but I/we digress. 
I'll bow to your knowledge of the OSX system. Haven't had chance to do much with that myself.
Marc, if you remember from the logs I gave you a few weeks ago, my MIDI driver was crashing.
I can't remember the details, but did it look anything like this?
Ah yes - the classic null pointer de-reference issue.
I've recently started working with ARM after years of working with MIPS.
You get used to MIPS handily core-dumping on null pointer de-references, then you get a shock because ARM maps addressable memory down at address 0, and for a while you can't understand how your program is still running!
I have 2 working systems and one not working. I usually run Cubase 8 Pro or Ableton Live 9.
Working well (apart from the usual arpeggiator timing issues):
Windows 8.1 64 bit on a self-built PC, with an Intel QX9650, Asus motherboard (can't remember specific model). Using 3x RME Multifaces for 24 analogue ins and normally 1 stereo pair of analogue outs. This has been my main system for at least 5 years.
A 2011 13" Macbook Pro with an i7. OSX 10.10.3. Virus works as sound-card and plug-in. Used it many times for gigs as a sound-card and synth (not plug-in in that scenario). It has 2x USB 2.0 ports.
Not working well - distortion and pops/clicks:
A 2013 Mac Pro running OSX 10.10.3. Nothing else plugged into the system apart from the Virus. Wireless keyboard and Magic Mouse on Bluetooth, although have also used a USB keyboard and mouse. Plugging Virus in anywhere (hub or directly) causes the Cubase dongle to fail. RME Fireface UC is working fine on USB. Will at some point buy a Thunderbolt enclosure and move my Multifaces onto this new system. Seems USB3.0 doesn't efficiently deal with Virus' USB somehow. May have to try a Kanex Thunderbolt to USB adapter.
Something which is worth mentioning, because I've fallen down this hole in my move from Windows to OSX.
It looks like on OSX, the Virus has to be powered up before the Mac.
On Windows, I could power up the Virus at any point before the DAW (Cubase or Ableton) is run.
If I power up the Virus first, I can usually get the plug-in to run, but with pops and clicks / distortion.
Sure, I'm talking about symptoms though.
It might be worth mentioning that this (on the surface at least) is pretty-much the exact same issue I've been having, except I'm on a real Mac Pro.
Spoke too soon. Virus didn't work, and after Virus had been connected, the Steinberg dongle failed. It continued to fail after Virus had been disconnected. Works fine on my MacBook Pro though.
For others' interest, I've taken most of this off-line with Access support.
...but here's something others might find interesting:
For some reason, my Cubase dongle started throwing errors and refusing to talk to either Cubase or the license manager.
I disabled the Mac BlueTooth and so far, my dongle has been behaving.
It may be that on-board BlueTooth, which happens to be a 12mb device hung off the same USB chip, might be causing problems.
I’ll try Virus again with BlueTooth disabled when I get chance.
Sure. I should get time tonight.
Sent to your email? Any particular configuration you'd like set up?
Some of the problems described in this thread (not the Fusion drive related issue) sound very similar to what I'm seeing:
I'm having almost the same problem. This is interesting extra info - thanks!
I also have Steinberg's eLicencer and iLok2, plus Virus. Ultimately, I'm going to want to add a whole load of USB audio-related devices, e.g. Korg Kronos. Roland TD30, Line 6 HD500X etc., so I'm going to have to work out how to get Virus to play nicely with all this other kit.
By the way, this is my hub:
http://www.belkin.com/us/p/P-F5U234/
In theory, it is MTT, but maybe it actually isn't? That would potentially explain the problems I'm seeing.
Edit: I'm reading that later revisions of that hub (REV:2.4) are properly MTT, but older versions aren't.
That might explain it!
edit2: my hub is Rev 3, which should be MTT.
Edit3: so, I've tried Virus into my hub on its own. It won't connect at all via the hub.
With purely virus into the Mac, nothing else at all - I can get the sound-card output to work. As soon as I start the plug-in, I get ticks every few seconds or so.
I decided to shift from 44.1KHz to 48KHz on Ableton (reason being is that Ableton doesn't need the Cubase dongle). That cured the tick, but introduced another distortion. It sounds very much like the Virus clock isn't properly synchronising with the Mac. I've heard almost identical from my Kronos over USB if the clock isn't synched.
So, seems there's some sample conversion issue going on in there too maybe, which may be confusing things.
The only solution I can now think of, is to buy a Thunderbolt to USB dongle (Kanex?), but that's quite expensive just to get the Virus going. I'm not even completely sure it would work given the strange clock-sync issue.
Back to being a MIDI module for now then I guess. 
Edit4: I'll add that I've just tried my 2011 MacBook Pro, which also has OSX10.10.3. Virus is working perfectly well on there.
Here's a set of diagrams showing, at a simple level at any rate, what should happen on a MTT versus a single MTT.
http://www.tomshardware.com/re…usb-technology,677-3.html
In theory, the MTT hub should be able to cope with Virus and other USB devices since it *should* translate each device individually to USB2 back to the host.
Yep - I understand the MTT thing. Theoretically, the MTT hub will translate the 12MBit to USB2.0 speeds. However, I thought the whole point of MTT is that it will effectively translate each device separately to USB2?
I'll give it another try tonight.
So, to be clear Marc - you have Virus Ti connected to a 2013 (cylinder) Mac Pro? You're on OSX 10.10.3?
You have Virus connected to an MTT hub, with nothing else on that hub?
Where does the 7 port Belkin hub you mentioned elsewhere come into the equation? Do you just have the Virus connected to a 7 port Belkin, with 6 ports free?
I guess if Virus is going to be the only thing connected to that hub, I'll have to buy another Belkin MTT hub...? I have a fair bit of kit which ultimately needs connecting to USB.
Another interesting quirk.
If I have my Cubase dongle connected on my Belkin (MTT) hub at the same time as Virus, the Cubase dongle stops being recognised. Somehow, the Virus is killing it.
It's like Virus is sucking all the band-width or something...?
Same happens if I have both plugged in directly to the Mac.
I'm using the 5.1.1 beta (as I already said above). Both bit accurate and core audio fail in the same way. I've tried all buffer settings from minimum to maximum. I get the same issue if I use an RME device for audio and Virus purely for its plug-in.
When I say "reckon", I'm not implying anything. No need to get defensive. I'm saying that I'm told that you have it working at Access. I'm not saying that I don't believe you.
I'm working with your support guy to try and get to the root of the problem.
I'm a professional software engineer myself, and understand how lack of reproducibility hinders investigation, but there do appear to be more than a few people with similar problems.
Yep - I've just got a 2013 MacPro and my Virus won't work as a sound-card or plug-in without static distortion every few seconds.
I've contacted Access support and they reckon it works OK on their Mac Pro.
I've tried using my Belkin 4 port MTT hub, with no luck.
I've tried every combination possible with USB connections.
I'm on the latest Yosemite, the 5.1.1 beta and the latest Cubase 8 Pro and Live 9.
Virus works OK on my 2011 MacBook Pro. I've done a fair few gigs with that combi.
So - I'd say there's an incompatibility with Virus Ti and the newer USB 3 ports and internal hubs.
I think Access need to take a deeper look at this.
I''m interested in this too.
I'm thinking of going for a Mac Pro this year, which only has 4 USB3 ports.
I've used my Virus as sound-card and synth for live sets on my 2011 MacBook 13".
So, I'm thinking either:
1) Dock with more USB ports (like the Belkin)
or
2) audio streamers like the Virus connected to 3 ports on the Mac and a hub for less time-critical devices.
Any thoughts or suggestions welcome.
