I'm having some problems with a USB CDC device under Windows 10, using the ASF 3.31.
It seems like the new usbser.sys drive is quite aggressive at suspending the device. Even if you disable selective suspend for USB, it does something that causes apps to crash and the device to send/receive odd characters. For example, if I open the virtual COM port in Putty, it becomes unstable if the Putty window loses focus!
Apparently usbser.sys has been rewritten for Windows 10 and there is even an entire new API for it, but of course apps that need to support Windows 8 and below can't rely on that. I have my own app which uses standard CreateFile() calls to access the port, which I guess is probably what most apps do (I tried Putty and HyperTerminal too). My device is not getting USB_SUSPEND callbacks, and I can see with a scope that the USB clock doesn't go away. It's something in the driver...
Has anyone else experienced this?