I have the same problem.  Any audio program using the Madiface drivers will freeze from within 60-seconds to 10 minutes and require a hard boot (can't even do a force quit).  I've tried Nuendo, Logic, Live and Plogue Bidule.  I have two identical MacBook Pros, and it is doing the EXACT same thing on both.

Computer is Macbook Pro 17", 8GB RAM, Mac OSX 10.6.1.  Madiface is at Firmware Rev 11 and driver version 2.70.

I've disabled literally every driver on the system that is not stock Apple and comes with 10.6.1, so it is not a conflict with another driver or device.  My guess is this is a Snow Leopard incompatibility.  Unfortunately, as this is a new machine that shipped with Snow Leopard, I cannot downgrade the machine to test the theory.  It will even freeze using JackOSX to wrap the RME driver.  There is definitely a problem with the Madiface in conjunction with a Macbook Pro and Snow Leopard.

Could someone from RME please comment?

Unfortunately, no I cannot reduce my memory to 2GB. There are two 4GB chips in the machine and currently it's being used in a studio setup, so taking it apart isn't an option right now.  And just to be clear, this isn't an error. This is a hardware level freeze requiring a complete hard reboot - no error messages, no spinning beach balls.  Literally just a complete lock up of the entire machine. 

I don't want to shut down the option of trying this with 2gb of ram, but I would be very surprised if memory has anything to do with this.  Usually any memory related errors result in a program shutting down or in an error message or other random behavior like that.  I've never seen a situation where memory in conjunction with a specific hardware piece would cause a complete lock up.  Also, the large percentage of Apple's machines now ship with at least 4gb of ram stock, so I would hope any testing that is being done at RME would be with at least 4GB or more.

FYI, all hardware, including the RAM passes Apple's Hardware Test (excluding the RME card of course, which Apple's program cannot test).

Hi, any updates on this?  I'm completely dead in the water.  Also, just so you know, I can re-flash the firmware of the cards successfully several times in a row, so it is not an issue with the ExpressCard slot on either of the two machines.  It definitely points to an operating system/driver issue.

Thanks for your attention to this.  I'm convinced you will be able to replicate the problem on any new unibody MacBook Pro with the same specs (8GB of RAM, 10.6 Snow Leopard, RME Drivers 2.70 and Firmware 11).