MC 6000 MK2 crossfader

Hi, Just wanting advise. Just recently I have noticed that my cross fader does not work. I have upgraded it using the latest software upgrade then it works but when I switch off the controller and turn it on again, same problem with crossfader. How can I address this? Thank you

Try some switch cleaner in it. Inject a small amount and slowly work it back and forward to clean the contacts.

No cleaning will help here. This looks like a software issue. Check mappings and how the controller communicate with the computer. Download midiOX and check what data the crossfader sends and what happens when it stops working.