Sudden barrage of "too many open files" in log, cascading app failures
So the problem turned out to be in Adobe CC. I ran the Adobe CC UNinstaller, and selected "Repair", rebooted, and things were back to whatever normal is. I just wish I'd connected Core Sync with Adobe sooner!

Oh, and in case anyone is interested, here's the script I used to figure what had the most files opened. It lists all the processes by name, and sorts by number of open files.


#!/bin/bash
lsof +c 0 | gawk '
{
    if (! $1 in count)
        count[$1] = 0
    count[$1]++
}
END {
    for (var in count)
        print var, count[var]
}
' | sort -n --key=2


It depends on GNU awk (gawk) so not sure how well it would work with the installed awk.