I seem to have a USB connection that's a little flaky and will address it.
When my iPhone, connected to my MacBook made that sound it does when it is first connected a few times in rapid succession, this message appeared.
I snapped a quick screen shot, unplugged my phone and clicked
Not Now rather than Learn More, or check Activity Monitor, so I can say much more than "this is how it looked," and no matter how I wiggle the connection I can't reproduce it.
It looks vague and ominously non-Apple, for reasons I can't explain. Is this a standard thing to happen, or is it weird or even potentially dangerous?