Following (and suffering) this issue for months now. Yes, there was even an update from Parallels that didn't address this issue. In the end, I just wrote a cron script that checks every 5 minutes if the bsdtars are running, and then kills them, and got on with my life.
Here's the cron script. I named it 'killbsdtar':
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#!/bin/bash
# crontab -e
# then add the line (press i, then paste):
# 00,05,10,15,20,25,30,35,40,45,50,55 * * * * /Users/<your username>/bin/killbsdtar
# and save the file (type :wq)
log=~/bin/killbsdtar.log
#echo "$(date) $0 started" >> $log
n=$(ps -ef | grep "tar -czf /Users.*toolbox_report" | wc -l)
if (( $n > 3 )) ; then
killall -9 tar
echo "$(date) killed $n running instances of bsdtar" >> $log
fi
#EOF
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You can install it with the command on the second line (without the # of course). You (as user) must be the same user that uses Parallels Desktop, and/or you must have sudo permissions to let the killall work.
For alternative intervals for running, take a look at
https://crontab.guru/examples.html
For you guys at Parallels reading this thread, here's my log file to date:
Fri Jul 10 18:45:00 CEST 2020 killed 15 running instances of bsdtar
Tue Jul 14 09:25:02 CEST 2020 killed 16 running instances of bsdtar
Tue Jul 21 09:25:01 CEST 2020 killed 16 running instances of bsdtar
Tue Jul 28 08:05:01 CEST 2020 killed 17 running instances of bsdtar
Tue Aug 4 08:05:00 CEST 2020 killed 18 running instances of bsdtar
which proves:
* it is a longstanding issue (it started with 5 or 6 bsdtars, a long time ago, now there're 18)
* it is a serious issue (having 18 processes running all claiming 100% cpu is no joke)
* it gets worse over time (15, 16, 17, 18, ...)
* it happens about every week and often after a reboot
FIX THIS, please. There's enough hints in this thread as to the cause.