Hi,
I have my UCX for 2 years now & from the beginning there was a problem with 'glitch sound' but I guess that's occure because of high CPU and latency/buffer size settings (sometimes glitch sound also occure when I'm pluging the cable into my Mac).

It also takes more time for UCX & TotalMix to connect/find each other & it's not so 'smooth' because sometimes TM asks me if I want to open default template or no & I have to wait for connection much longer than I used to.

But recently I noticed that my led OUT1 is blinking all the time, but only when I am using USB (when using FireWire everything seems to be ok). I have the latest drivers and latest OS. I also checked different USB cables. I also noticed that when I turn off TotalMix, then led stops blinking (this must mean something). I am sure that something's wrong, but really don't know what. I contacted with RME representative in my country & they told me that they can send my RME to Germany to check whats wrong with my unit, but It would take at least 3 weeks & I really can't afford it, plus I think that's must be something wrong with drivers/my mac/settings etc., not with UCX hardware.
Please let me know what could be wrong with it.

https://www.youtube.com/watch?v=rj1USclmwjk - Blinking diode