There are many old threads on this topic. They are old. I re-read them and nothing suggested worked. My answer was always to start it as boincmgr in a root terminal. That no longer works for me. In the boinc manager, I get the status that communication is deferred. It is in a loop. It never downloads work. I have updated via yast and when that didn’t work, I downloaded via flatpak. That didn’t work either. This may be helpful:
localhost:/var/lib/boinc # systemctl status boinc-client
× boinc-client.service - Berkeley Open Infrastructure Network Computing Client
Loaded: loaded (/usr/lib/systemd/system/boinc-client.service; enabled; preset: disabled)
Active: failed (Result: exit-code) since Sat 2025-09-20 20:20:28 EDT; 12min ago
Duration: 10.037s
Invocation: 310757fce3fa469f9dfd3934df6ac698
Docs: man:boinc(1)
Main PID: 78790 (code=exited, status=108)
CPU: 0
Sep 20 20:20:18 localhost.localdomain systemd[1]: Started Berkeley Open Infrastructure Network Computing Client.
Sep 20 20:20:18 localhost.localdomain boinc[78790]: 20-Sep-2025 20:20:18 [---] cc_config.xml not found - using defaults
Sep 20 20:20:28 localhost.localdomain boinc[78790]: 20-Sep-2025 20:20:28 Failed to open lockfile. Check file/directory permissions.
Sep 20 20:20:28 localhost.localdomain systemd[1]: boinc-client.service: Main process exited, code=exited, status=108/n/a
Sep 20 20:20:28 localhost.localdomain (rm)[78829]: boinc-client.service: Invalid environment variable name evaluates to an empty string: BOINC_BOINC_DIR/lockfile
Sep 20 20:20:28 localhost.localdomain systemd[1]: boinc-client.service: Failed with result 'exit-code'