My usually rock solid setup has been suffering from crashes for the last few months.  When I finally had a few minutes to look into it, I came here to the forums (of course).  
 
I was able to identiify a particular plugin that was causing the "white out" freeze.  But even after those were all replaced i was still experiencing this freeze where, even after I ended the program, Sonar.exe was still running as a process.  I could not end the process or the process tree.  After a few minutes, it ended on it's own.   It was excruciating waiting for it to end while clients stood by.  I could not start sonar until the process ended and cycling the interface did not help.
 
ACCORDING TO A POST I FOUND HERE ON THE FORUM, this can be caused by midi interfaces.  I checked my computer and sure enough, my old m-audio midi sport uno thingy was hanging out of the back of the machine not connected to any midi devices.  Someone needed it one day and then it was just left there dangling from a usb port amongst the dozens of cables and wires.
 
i wound it up and put it away and i am back to rock solid!  I would NEVER have thought it was possible.
 
 

Did you ever update its drivers? It would be interesting to confirm the crashes if it was plugged back in and new drivers were installed.

m audio seems to take their time updating drivers for devices.
so when i hear "are the drivers up to date" ?
it makes me think, is it the one they released in 09 ? 

A driver set from 2013 is available for the MIDIsport Uno.

i will update, thanks.  rarely use it but i will NOT forget the hell it put me through.  

The drivers for my M-Audio Ozone were intrusive and even when I kept running it as only a controller I had to uninstall the drivers and route it via MIDI cables. The unit was not class compliant and could not be used via USB without those drivers. ASIO4ALL drivers had a similar effect years ago on another machine, so driver conflicts can be issues even with a driver simply installed :(

chuckebaby
m audio seems to take their time updating drivers for devices.
so when i hear "are the drivers up to date" ?
it makes me think, is it the one they released in 09 ? 

For portable, non-rackmount USB MIDI interfaces, there aren't too many options out there. M-Audio (and the old Midiman interfaces) are about the most versatile out there. Perhaps the poor driver support most likely stems from the overall lack of demand for MIDI interfaces. 
 
I chimed in on this thread because I have a Midiman Midisport 4x4. It looks cheesy by gets the job done for my hardware. I also get weird, unexplainable white-screen crashes at times, so I have an interest in the outcome of the OP's predicament. If the problem clears up, then perhaps I could experiment with a MOTU Micro Lite 5x5 which is from a reputable company, and it isn't too bad price-wise. The M-Audio 4x4 Anniversary Edition, in my opinion, is probably no different inside than the older Midisports; they're just rebranded, reboxed and repainted.

Not to pile on, but...
 
Never been a fan of M-Audio drivers. Moved away from them a few years ago and been happy ever since. I s'pose everyone's experience is different, however...

I'll never do it again.

Living Room Rocker
I'll never do it again.

So dramatic! So what was your alternative?