'Did I understand you correctly, the problem no longer occurs?'

No, still happens. I mean that it doesn't happen if it's a device that's not connected to Live, again suggesting it's to do with Live.

 

I'm going to try an old version of Ableton.

 

Yep, I'll do that.

 

And Live is installed in the Windows environment!

 

Ok, it's Ableton. Works fine with the earlier version of 12. I'll just have to put up with it until it's sorted as none of my tracks open now. Thank you for the support, greatly appreciated.

 

It's not your usb cables, your synth, your audio interface, or your operating system. Some problem like this which is working in an older version of the DAW software should really not dramatically change from one build to the next, when it comes to stuff they already had working. New features in a beta, or things like that may be broken, but not basic functionality of something as simple as hardware synths.

You might want to try a newer version again to get your projects back open. You could try reinstalling the new version from scratch, with all default settings. You could try to disconnect all usb devices from the computer before you start the reinstallation. You should not have to, but it would not hurt.

 

I found A12 so unreliable ... i'm back to A11