I've been recording for about one year with this soundcard.
Stereo Pair - Neumann KM 184 (fantom power provided by card)
Stereo Pair - AKG 414S (fantom power provided by card)
MacBook PRO 12 inch running Mac OS High Sierra Logic Pro X latest version
Of course the thunderbolt connection has to go through an adaptor to use the newest USB C ports on my new Mac Book Pro.
Well first day of recording as usual smooth.
We started the second day's session two days later.
When I replugged in the microphones (I had left the cables in place) and the thunderbolt and other connections I had cracking or hum on lines 3 and 4 (the KM 184s).
I unplugged the mics, turned off the fantom power and even the soundcard. All seemed OK. But then not while the music was being recorded (at least not audible) the cracking and hum came back at the end of the piece in the fading sound. Not all the time but sometimes, unpredictable and in only channels 3 and 4 (I repeat the Neumann mics).
I did get a "no hardware connected" message when I fired up and then realized I had not pushed the Thunderbolt connection in as far as I needed to in the Mac.
So any brilliant ideas?
Mine are :
1 - Maybe the cables were damaged in between the two sessions
2 - I should have rebooted all after plugging the thunderbolt cable in correctly
3 - I overloaded the RAM by preparing about 40 tracks instead of recording just 4 at a time and then adding as needed.
I've googled this and updated my driver (Focusrite Control) although not sure it was necessary and I might have had the most up to date one already. I have NOT yet installed the latest fix to High Sierra.
Thanks to all for any suggestions or help, it is making me CRAZY!!!