My guess would be that pkexec/policykit is complaining about having a path in $TERM.

I opened the LXQt Configuration Centre and from there opened the Session Settings and in the Default Applications I set the Terminal Emulation to rxvt-unicode-256color (previously it was /usr/bin/rxvt). Then after I had logged out and back in, I was able to run Synaptic and Gparted from the menu. I then removed policykit-1-gnome and after logging out and in, it still all works.

As you say I have lxqt-policykit installed and ps reports that /usr/bin/lxqt-policykit-agent is running.

Geoff

Now, I noticed there is no selection for lxterminal in the Preferences>Session Settings>Default Applications.  So I manually changed <home>.config/lxqt/session.conf to:

TERM=LXTerminal

Rebooted, and all is ok now with using lxterminal; can run synaptic/gpartd from menu.

I think atleast for me the problem was not having a valid entry for TERM= in the <home>.config/lxqt/session.conf file.

Note I am using lxqt-policykit,

After a recent upgrade I have had some problems with some authentication. For example, selecting synaptic from the menu fails to run. I see in the thread about pkexec https://dev1galaxy.org/viewtopic.php?id=2667 that it is recommended to install  policykit-1-gnome. I have now done this and it has not caused any problems and I can run synaptic from the command line as synaptic-pkexec. I am still unable to run synaptic from the menu (using LXQt). Looking in /var/log/auth.log I can see that pkexec is complaining :-

The value for environment variable TERM contains suscipious content

In my window, $TERM is set to rxvt-unicode-256color. This doesn't look suspicious to me, but I am not pkexec! I wonder what it is picking up and what is wrong with it.
I have installed gparted and can run it from the command line but not from the menu, which gives the same error about TERM.

Geoff

Odd.  I am now having the very same problem, with synaptic, in LXQt.  Cant run from menu but can from terminal.  I just switched from using qterminal to using the old lxterminal.  Have the same error as you and same env value: TERM=xterm-256color.  I did not have this problem until I switched to lxterminal.  Will do some more research.

The value for environment variable TERM contains suscipious content

In my window, $TERM is set to rxvt-unicode-256color. This doesn't look suspicious to me, but I am not pkexec! I wonder what it is picking up and what is wrong with it.
I have installed gparted and can run it from the command line but not from the menu, which gives the same error about TERM.

Geoff

Any thoughts on how to troubleshoot?

Thanks, Rolf

everything's working fine here with newer policykit (no ascii repos anymore).
just saw your post about upower, and will be trying that also soon.

Noticed this on the laptops the other day when my hardware warning light started flashing even though the icon said 98%!

Thanks for posting the notice, I'll remove pinnings this weekend and see what happens in Cinnamon!

I have now moved to the newer versions by using force-version in Synaptic, which refers to it as a downgrade!

Geoff

Looking at where all the packages come from, with fsmithred's command, nearly all are from testing, with just a few being labelled "now".  If I grep for not testing then I find :-

aptitude search ~i -F"%p# %v# %t#"|grep -v testing
clearlooks-phenix-darkpurpy-theme 7.0.2-1+devuan2.0 now
darkpurpy-icon-theme 1.0 now
desktop-base 1:2.0.3 now
devuan-baseconf 0.6.4+devuan2.3 now
gnome-icon-theme-extras 3.12.0-1 now
libupower-glib1 1:0.9.23-2+devuan1.3 now
upower 1:0.9.23-2+devuan1.3 now

These must have been pulled in from ASCII when I was installing the earlier policykit stuff.

I believe that Golinux is working on the theme for Beowulf.

There is a newer version of upower in testing but the version number is 0.99.9-3 and there is no matching version of the library. I recall that there was a problem as to which version number would be taken as higher if there is a "1:" in front.

Geoff

My package versions:

dxrobertson@acer:~$ apt list --installed | egrep "polkit|policykit"

WARNING: apt does not have a stable CLI interface. Use with caution in scripts.

libpolkit-agent-1-0/testing,now 0.105-25+devuan1 amd64 [installed]
libpolkit-backend-1-0/testing,now 0.105-25+devuan1 all [installed,automatic]
libpolkit-backend-elogind-1-0/testing,now 0.105-25+devuan1 amd64 [installed]
libpolkit-gobject-1-0/testing,now 0.105-25+devuan1 all [installed,automatic]
libpolkit-gobject-elogind-1-0/testing,now 0.105-25+devuan1 amd64 [installed,automatic]
libpolkit-qt5-1-1/testing,now 0.112.0-6 amd64 [installed,automatic]
lxqt-policykit/testing,now 0.13.0-1 amd64 [installed]
policykit-1/testing,now 0.105-25+devuan1 amd64 [installed,automatic]
dxrobertson@acer:~$ 

Clarification:  I can mount/unmount from within file manager pcmanfm-qt.  Wireless network working with NetworkManager.

The initial report is that the basic stuff still seems to work, but KatolaZ has asked that the stuff round the edges is tested...

Geoff