How do I get the "The disk you attached was not readable by this computer" windows to stop popping up continuously?

I'm running macOS Big Sur, Version 11.2.2, on an iMac bought in the autumn of 2020. Since the last system upgrade, these "The disk you attached was not readable by this computer." windows often pop up at any time, like in Zoom video meetings and other inconvenient times. When the windows pop up they interrupt typing. Sometimes when I walk away from my computer and return, my screen looks look the included picture and it takes me around 5 minutes to clear the multitude of windows that popped up while I was away from the computer. Is there a way to turn off these pop-up windows to stop this insanity?

I have a backup disk attached to my computer and a USB hub. These are the same devices that were attached to my computer with the previous system and this didn't happen. Nothing changed but the system. These pop-up windows are a feature of the new system software. I've gone into preferences and see no way of affecting this. Thanks in advance to anyone who can help stop this craziness.