OK not a FF800 but UFX connected on firewire and the OSX update does not seem to have hurt anything.

Sorry my English s**t
I have problems with my RME 400 and OS X Mavericks.
If you open Logic pro and play music on Safari 7.0, the sound becomes distorted, crackled.
If you close Logic pro sound good on Safari

if you control the volume from the keyboard it is slow

What can you say about my problem? My setup MacBook Pro 15 2012 RME 400

Any.

Because my English is still poor,
I might sound rude to you.
Please forgive me and understand (that) I never mean it.

I updated it in OS X Mavericks (MAC OS X10.9).
The version of the FIREFACE800 driver is the latest, too.
However, I am hit by the consecutive troubles of the beep sound which crashed on the way
when I play a sound in FIREFACE800.

[my MAC use environment]
iMAC (27inch,Late2013) 3.5GHz Intel Core i7
Memory 8GB 1600Mhz DDR3
HD 3TB

<audio system interface>
I am connected to the cause with Thunderbolt ? Firewire800 conversion cable.
RME FIREFACE800

Yes.
I think that the version of my FIREFACE800 is the latest.
The version of the driver is 3.17 and Rev. 2.77.
And software updates of MAC OS X(10.9) is the latest, too.

I was able to use it without a problem in MAC OS10.8
Until a few days ago

I updated it in driver is 3.18 and Rev. 2.77 Kernel=3.18,
but the trouble that asked you a question was not solved today.

I figured out my original issue - needles to say it was me not the software.

I think that probably the sound crash skip phenomenon
that asked you a question is caused by Fusion Drive of iMAC (27inch,Late2013) or MAC OS X10.9 so far.
It was written in at a discussion forum of Aple that this phenomenon occurred in the audio system interface of other companies.
My problem is not still settled, but thinks that a user hit by a trouble like the future comes out by all means. Therefore I think that I serve as some kind of references.
Thanks

Someone has a problem I described above?

This is not an issue of 10.9, but of the Fusion Drive equipped iMac systems. Only Apple can fix this.

Regards
Daniel Fuchs
RME

The issue with audio breaking up after a few minutes is a known Fusion Drive problem, as you will find on this forum and elsewhere on the web. The other issue with the Macbook is likely unrelated.

Regards
Daniel Fuchs
RME

I'm using an RME 400 and MacBookPro 2012, i'm getting sound but it's skips/hangs/freezes a lot when loading a webpage or programms. Never had this problem with Mountain Lion.

I just had a show with some interesting clocking things happen while using my rMBP running 10.9 and my UC.  I usually use my trusty 2011 MBP running Lion and probably old UC drivers, but just before a big show a month ago its logic board died, and I figured a 13" Haswell with a 512G internal SSD would be a great backup and eventual replacement.  Last week I got off the plane at another gig and the 2011 MBP had its battery swollen and was bulging at the seams so I decided to use the new 13" running Mavericks again until I could get the battery replaced.

I'm a corporate A1 who runs a bunch of playback and some records with my UC, usually via ADAT connection.  Depending on the console I rent, sometimes I clock it to my Fireface because lots of companies send them out with Black Lions and I like my RME clock next to those (I'm not sure I hear a difference clocking the consoles or leaving them be) and occasionally that will clean some noisefloor out of digital snakes.

That's how I was setup, Yamaha M7 chasing my UC which I've done dozens of times, and everything seemed OK through setup and soundcheck until I took the setup apart to record voiceover announcements in a quiet room.  It was the first time I had run Logic on this new 10.9 machine, downloaded fresh from the App Store.  I started an empty project, pointed Logic at my RME as default IO device, changed the project sample rate to 48K then recorded a dozen or so voiceover snippets.  Then I hooked my UC back up to the console, took my laptop back to my hotel room to edit on headphones and go to bed.

Pretty sure I didn't reboot the machine, I edited the VOs, bounced them, quit Logic and shut the lid.  The next morning I plugged my laptop into the UC and everything in the PA popped, which hadn't happened before.  Then I started trying to review the VOs I had recorded on the PA and a lot of them had obvious sync issues, stuttering and popping.  Then I went back to my soundboards (I use QCart) from the day before, all cues that had fired perfectly fine many times and they started doing the same thing, as did iTunes.

I had a whole crew waiting for me to start a rehearsal so I quickly rebooted (did not power cycle the Fireface) and that seemed to make everything happy again.  At least one other time I had the PA pop like it lost sync briefly when I plugged the laptop into the UC, but most times that didn't happen and the playback never crashed like that again.

I've had this UC since within a few months of its release, with the 2011 15" it has been rock solid, and it was flawless with the older MBP I had before that (2008 maybe?).  I've gone through this whole process dozens of times and never experienced these issues, even with 10.9, but it seems like switching between the UC and onboard sound Logic somehow managed to break the sync of OSX applications and at least stutter the outgoing clock signal from the Fireface.