"usermod: user user is currently used by process" while using (trying to) thunderbird to back up my gmail account's data ...

[Albretch Mueller <lbrtchx@gmail.com>]

 on debian live:

$ uname -a
Linux debian 5.10.0-18-amd64 #1 SMP Debian 5.10.140-1 (2022-09-02)
x86_64 GNU/Linux
$

 I am running:

$ thunderbird --version
 Thunderbird 91.13.0
$

 to download all the data in my gmail account via POP3, but
Thunderbird seems to be making assumptions about where to put your
data and I haven't found a way to tell it where to put it; so, since
it uses the user's home directory, the only way I think you could
easily put the data where you want is by changing it, but I can't:

$ usermod --move-home --home "${_NEW_HOME}" "${_WHMI}"
usermod: user user is currently used by process 1141

$ sudo ps -aux | grep 1141
user        1141  0.0  0.1  15600  9144 ?        Ss   Nov05   0:00
/lib/systemd/systemd --user
user       50636  0.0  0.0   6244   712 pts/0    S+   06:42   0:00 grep 1141

 Unless they are both trying to exclusively access /etc/passwd, I
can't understand how /lib/systemd/systemd could possibly relate to
usermod.

 Any suggestions?