boinc --version: 7.24.1 x86_64-pc-linux-gnu, running on Mageia 9
Starting boincmgr gives an error message that " BOINC Manager is unable to start a BOINC client. Please run the client and try again"
So as root: systemctl start boinc-client.service gives the error code 192, which one search suggests client_state.xml is not writable.
It isn't:
-rw-r--r-- 1 boinc boinc 99884 Sep 21 11:45 client_state.xml
However, after making it writable:
-rw-rw-rw- 1 boinc boinc 99884 Sep 21 11:43 client_state_prev.xml
-rw-rw-rw- 1 boinc boinc 99884 Sep 21 11:45 client_state.xml
Sytstemctl start boinc-client.service
Sep 21 13:57:24 haydn.gemmill.name systemd[1]: boinc-client.service: Failed with result 'exit-code'.
Sep 21 13:57:24 haydn.gemmill.name systemd[1]: boinc-client.service: Main process exited, code=exited, status=64/USAGE
Sep 21 13:57:24 haydn.gemmill.name boinc[141301]: Error Code: -192
and client_state.xml is replaced by a read-only version:
-rw-rw-rw- 1 boinc boinc 99884 Sep 21 11:45 client_state_prev.xml
-rw-r--r-- 1 boinc boinc 99884 Sep 21 13:57 client_state.xml

Can't find anything relevant on Google,, so I would like some ideas please.
Thank you
Graeme

client_state.xml is replaced by a read-only version

EXIT_STATEFILE_WRITE 192 - The client will exit if it cannot write to the client_state.xml file. Make sure you have permission to write to the BOINC Data directory.

EXIT_STATEFILE_WRITE 192 - The client will exit if it cannot write to the client_state.xml file. Make sure you have permission to write to the BOINC Data directory.

sudo usermod -a -G boinc yourusername

will add you to the boinc user group. I do this routinely on my linux installations.

Was already a member:
boinc:x:977:graeme

Have you tried changing the read-only attribute of the client_state.xml file?

Message 112725 describes the problem remains after doing so. I don't know the distro in question and I haven't used Mandriva which it is a fork from for about fifteen years. I am wondering if it is a distribution specific problem. I found Mandriva messed around with things too often for me though I can't remember exactly what now. I used it's predecessor, Mandrake for about four years.

Yes, see the original post; the new version is made read-olny.

Post your boinc-client.service file contents at /etc/systemd/system/boinc-client.service.d/

Likely the service file is setting up the wrong read-write permissions.

Do you have this in the file? It helps with the newer distros and clients.

PrivateTmp=true
ProtectSystem=strict
ProtectControlGroups=true

Post your boinc-client.service file contents at /etc/systemd/system/boinc-client.service.d/

If it exists. It doesn't on my set up but that may be due to my having compiled from source and not installed via the package manager?

Actually at /usr/lib/systemd/system/

[Unit]
Description=Berkeley Open Infrastructure Network Computing Client
After=network.target

[Service]
Nice=10
User=boinc
Environment="DISPLAY=:0"
ExecStart=/usr/bin/boinc --dir /var/lib/boinc
ExecReload=/usr/bin/boinccmd --read_cc_config
ExecStopPost=/bin/rm -f /var/lib/boinc/lockfile

[Install]
WantedBy=multi-user.target

No boinc-related service files in /etc/systemd

usr/lib/systemd/system/system

Has the following

[Service]
Type=simple
ProtectHome=true
ProtectSystem=full
ProtectControlGroups=true
ReadWritePaths=-/var/lib/boinc -/etc/boinc-client
Nice=10
User=boinc
WorkingDirectory=/var/lib/boinc
ExecStart=/usr/local/bin/boinc
ExecStop=/usr/local/bin/boinccmd --quit
ExecReload=/usr/local/bin/boinccmd --read_cc_config
ExecStopPost=/bin/rm -f lockfile

So different location depending on distribution I guess.