I have several problems concerning my new fireface uc:

1. Sometimes, when I switch off the uc, my macbook crashes. That I means that the "grey screen" will appear and I have to restart my computer. But there is no audio running at this moment.  Isn't it possible to switch off /disconnect the uc while the computer is running? It would be very useful to do that. I thought that USB is able to be hot-plugged. In Mac, unlike in windows, there is no possibility to "unmount" usb-devices.

2. Last time I switched the fireface on, the host led lighted at the following rhythm: appr. 5 seconds on, then 3 times shortly on/off. This cycle repeated until I restarted the fireface. Then everything went fine. Is this a error code, perhaps a hardware issue?

3. Sometimes (not very often) I get distorted audio in several applications. The error can be fixed by switching  the sample rate in the settings dialog to for example 48kHz, then back to 44.1kHz. Often but not always switching the latency helps also.
I saw in this forum, that this problem occurs with several kinds of rme hardware, either firewire, pci or pciam, on mac and on pc.
Is there the possibility of a driver update in near future? I tried other interfaces and onboard sound, there the problem didn't occur. So it SEEMS to be RME related.

4. Last time,when I burned a DVD, suddenly the host led lighted. I was not able to rebuild the connection by restarting the fireface, until the DVD was finished. The only running audio app was iTunes. The cpu load was not very high at this moment. This may not be a very critical error, but it is not very useful, that you even can't use system sounds or iTunes, while simply burning a dvd.

I would be thankful for suggestions on these issues. I'm still in a testing period for the uc and I'm very interested in stability. So I'm still undecided if I should retain the uc or switch to other stuff.