Without any warranty as I did not find any documentation about this.
Just tried to find files which were updated when changing the logging level either with the GUI or the command line using PLUGIN subcommand.
In my Documents folder, I have this subfolder structure:

The content of prefs.dat text file is the following:
#com.ibm.iaccess.base.AcsGlobalConfig Last updated on Fri Oct 31 18:07:54 CET 2025 by process with PID pid_28072_fd935be2
#Fri Oct 31 18:07:54 CET 2025
autocheckupdate\:\ is\ enabled=Yes
checkupdate\:\ system=
descriptionPanel\:\ is\ enabled=No
diag\:\ log\ level=OFF
file\ chooser\:\ window\ height=399
file\ chooser\:\ window\ width=582
general\:\ accessible\ mode=No
lm\:\ cache\ time=600
locale\:\ country=US
locale\:\ language=en
locale\:variant=
netrc\:\ snooping=No
ssh\:\ private\ key=C\:\\Users\\Marco\\OneDrive\\Documents\\IBM\\iAccessClient\\privatekey.openssh
ssl\:\ default\ all\ comm\ to\ ssl=No
ssl\:\ fips=No
tooltip\:\ is\ enabled=No
I have played to change "diag\:\ log\ level=" setting with one of the allowed values as found in the GUI. It looks to work.
You may want to give it a try. Be aware that a prefs.dat file exists in most of the "client.configuration" subfolders
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Marc Rauzier
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Original Message:
Sent: Fri October 31, 2025 10:42 AM
From: Stuart Bramley
Subject: Set logging level to OFF in ACS for all users
It's set in Edit > Preferences > Logging level

We deliver ACS centrally via Citrix so have control. I assume there's a Java property that controls it and that we could set.. but don't know what it is - there's nothing related to logging in the AcsConfig.properties file..
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Stuart Bramley
Original Message:
Sent: Fri October 31, 2025 10:33 AM
From: Marius le Roux
Subject: Set logging level to OFF in ACS for all users
Stuart,
How did they manage to get that setting on in the first place? (I cant find any options in this readme : https://www.ibm.com/support/pages/ibm-i-access-acs-getting-started)
My reactive measure though as suggestion is if you can and are allowed to , let them only use Acs from a central location that you as an admin can manage?
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Marius le Roux theIBMiGuy
Owner , IBM i Modernization and Integration Consultant
MLR Consulting
Original Message:
Sent: Fri October 31, 2025 08:57 AM
From: Stuart Bramley
Subject: Set logging level to OFF in ACS for all users
Hi,
In ACS, is it possible to set the logging level to OFF for all users - e.g. via the ACSConfig.properties file? We have just had an issue where a user has inadvertently set this to FINEST and filled up the disk of one of our Citrix servers with an 80Gb log file.
I'd like to be able to manage this setting centrally to prevent it happening again.
Many thanks
Stuart
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Stuart Bramley
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