Hello!
I have a Keylab 88 and a Leem sustain pedal that won’t function properly together. The midi information from the pedal gets stuck on pressed down and I’ve tried using the polarity switch but it only reverses my problem. I figured the solution might be within Arturia’s MCC.
Since my MacBook only has thunderbolt I use a USB-hub which I understand can’t power my Keylab. This is why I have a seperate power supply and connect via midi to my Scarlett 2i2. Is it possible to get the Keylab to at least interact with the MCC through the USB-hub or do I simply have to find a new cable to connect it directly to my computer? I’m not able to use my Keylab to it’s fullest extent at the moment and it’s really bothering me.
Thankful for any help I can get, take care! 
Hello.
Hubs can sometimes mess the USB communication so we advise to avoid them, but in a lot of situations this will work perfectly.
I use a powered hub for pretty much all my devices and the MCC works well.
You may want to avoid hubs mainly for FW updates, which can sometimes be a bit unstable when done through a hub. But for the configuration of your device, it should not cause any issues.
The best you can do it try it and see if it works, but I would say it will.
Cheers !