Problems with random crackles in the recorded sound... a setup issue?

[voidpipe]

I am new to MuLab and are just trying to set it up properly on the new MacBook Pro with the retina display but have some problems with random crackles in the recorded sound.

First my setup:
MacBook Pro (Retina display version) with Mountain Lion and 8 GB of Ram and 500 GB SSD and Thunderbolt.
Apples Thunderbolt to Firewire conversion cable
Conversion cable from FW800 to FW400
Mackie Onyx 820i Firewire equipped mixer
Roland UM-1 USB midi interface

I try to record one stereo track of audio, one mono track and one midi track at the same time as this is my normal workflow from using a midi equipped Godin XTSA guitar through a Roland GR55 and I would like to capture the stereo sounds from the GR55 + midi created + the pure guitar sound.

When I play songs in iTunes or Spotify they sound great going through the conversion cables to the mixer but when I record some tracks into MuLab I get these random crackle that spoils it totally.

I am hoping for some hints on how to setup MuLab in a way so this can be handled in a better way….

[voidpipe]

I just want to let everybody know that this is solved for me now and it probably didnt have anything to do with MuLab.
Perfect sound now! ;o)

[megalodonnl]

It would help others if you mention how you solved the problem. I have the same problem suddenly. Did it have anything to do with recording to the SSD?