Mounting USB drive that is not recognized

Using Arch Linux / XFCE, I frequently have problems with USB drives that are not properly mounted. Sometimes they automatically show up in Thunar and I can mount them with one click. However, at other times (it’s about fifty/fifty) the drive is just not recognized. I have had this problem with USB External Hard Drives, USB Memory Sticks, and cameras. If the external drive is not recognized, this is the situation:

Debian + USB3 HDD + UAS: I/O errors

I’m running rsync to backup a remote machine to a USB hard drive on an ARM SBC and sometimes rsync just stops with “read error from input device (I/O error)”. I believe the issue is related to UAS + USB 3.0 + rsync causing high I/O load, because of uas_eh_device_reset_handler on /var/log/messages: