High sierra USB problems

High Sierra (10.13.1 and 10.13.2). I'm experiencing several problems with USB on two different iMacs.

1. USB hard drives unmount unexpectedly, mostly in the night (Put hard disks to sleep option is not ticked). This generally interrupts Time Machine. Although the drive is mounted in the morning, there are messages that have told me not to remove the drive, even though nobody has.

2. EyeTV DTT Stick, which is a USB device: the EyeTV program freezes. Removing the stick and plugging it back in often fixes the problem. Otherwise, need to reboot.

3. Often receive the message "USB Devices disabled", saying that some USB device(s) is using too much power. This never happened with OSX versions prior to 10.13. Usually three devices connected: EyeTV, iPhone and Toshiba 1Tb USB drive.

I have no solution, but the question is, is anybody else experiencing USB-like problems?