Chameleon Midi input not working anymore on in Ableton

Hello Marc
In critical environments, such as a PC you use for your performances, you should keep updates set to manual and instead force the update manually, for example, on Mondays.
Or at least configure it so that it only updates on a Monday, ensuring that if something goes wrong, you have enough time to fix any issues.

Regarding this case, I couldn’t tell you what’s happening until we can investigate directly on your PC, as this is not a widely reported error.
As a possible solution, back up your templates and their TSI files, then uninstall Chameleon, followed by uninstalling BOME MIDI.
Next, reinstall same version of Chameleon you are using.
This will likely solve the problem, but I can’t confirm it.
If it doesn’t work, you can try rolling back the Windows update to restore it to the previous state. Always make sure to back up before doing this.
Let me know if works.