Hello Marc, I did some more investigation as to the cause of the param errors I am experiencing with Koha since upgrading to 16.11. The following log entries from today seem to be revealing: gmasters@server1:/var/log/koha/library$ tail -10 *opac-error.log* [Fri Jun 02 16:43:55.057378 2017] [cgi:error] [pid 21358] [client 82.80.249.143:56285] AH01215: [Fri Jun 2 16:43:55 2017] 404.pl: DBD::mysql::db do failed: Table 'koha_library.sessions' doesn't exist [for Statement "INSERT INTO sessions (id, a_session) VALUES(?, ?) ON DUPLICATE KEY UPDATE a_session = ?"] at /usr/share/perl5/CGI/Session/Driver/mysql.pm line 50.: /usr/share/koha/opac/cgi-bin/opac/errors/404.pl [Fri Jun 02 16:43:56.352809 2017] [cgi:error] [pid 21381] [client 82.80.249.143:56395] AH01215: [Fri Jun 2 16:43:56 2017] 404.pl: DBD::mysql::db do failed: Table 'koha_library.sessions' doesn't exist [for Statement "INSERT INTO sessions (id, a_session) VALUES(?, ?) ON DUPLICATE KEY UPDATE a_session = ?"] at /usr/share/perl5/CGI/Session/Driver/mysql.pm line 50.: /usr/share/koha/opac/cgi-bin/opac/errors/404.pl [Fri Jun 02 16:43:58.982060 2017] [cgi:error] [pid 21390] [client 82.80.230.228:59667] AH01215: [Fri Jun 2 16:43:58 2017] 404.pl: DBD::mysql::db do failed: Table 'koha_library.sessions' doesn't exist [for Statement "INSERT INTO sessions (id, a_session) VALUES(?, ?) ON DUPLICATE KEY UPDATE a_session = ?"] at /usr/share/perl5/CGI/Session/Driver/mysql.pm line 50.: /usr/share/koha/opac/cgi-bin/opac/errors/404.pl [Fri Jun 02 16:43:59.306611 2017] [cgi:error] [pid 21393] [client 82.80.230.228:57266] AH01215: [Fri Jun 2 16:43:59 2017] 404.pl: DBD::mysql::db do failed: Table 'koha_library.sessions' doesn't exist [for Statement "INSERT INTO sessions (id, a_session) VALUES(?, ?) ON DUPLICATE KEY UPDATE a_session = ?"] at /usr/share/perl5/CGI/Session/Driver/mysql.pm line 50.: /usr/share/koha/opac/cgi-bin/opac/errors/404.pl [Fri Jun 02 16:43:59.583504 2017] [cgi:error] [pid 21396] [client 82.80.230.228:52914] AH01215: [Fri Jun 2 16:43:59 2017] 404.pl: DBD::mysql::db do failed: Table 'koha_library.sessions' doesn't exist [for Statement "INSERT INTO sessions (id, a_session) VALUES(?, ?) ON DUPLICATE KEY UPDATE a_session = ?"] at /usr/share/perl5/CGI/Session/Driver/mysql.pm line 50.: /usr/share/koha/opac/cgi-bin/opac/errors/404.pl [Fri Jun 02 16:44:00.432558 2017] [cgi:error] [pid 21399] [client 82.80.230.228:59790] AH01215: [Fri Jun 2 16:44:00 2017] 404.pl: DBD::mysql::db do failed: Table 'koha_library.sessions' doesn't exist [for Statement "INSERT INTO sessions (id, a_session) VALUES(?, ?) ON DUPLICATE KEY UPDATE a_session = ?"] at /usr/share/perl5/CGI/Session/Driver/mysql.pm line 50.: /usr/share/koha/opac/cgi-bin/opac/errors/404.pl [Fri Jun 02 18:18:26.003233 2017] [cgi:error] [pid 23865] [client 180.76.15.136:44399] AH01215: [Fri Jun 2 18:18:26 2017] opac-main.pl: DBD::mysql::db do failed: Table 'koha_library.sessions' doesn't exist [for Statement "INSERT INTO sessions (id, a_session) VALUES(?, ?) ON DUPLICATE KEY UPDATE a_session = ?"] at /usr/share/perl5/CGI/Session/Driver/mysql.pm line 50.: /usr/share/koha/opac/cgi-bin/opac/opac-main.pl [Fri Jun 02 18:18:26.017423 2017] [cgi:error] [pid 23865] [client 180.76.15.136:44399] AH01215: [Fri Jun 2 18:18:26 2017] opac-main.pl: DBD::mysql::db do failed: Table 'koha_library.sessions' doesn't exist [for Statement "INSERT INTO sessions (id, a_session) VALUES(?, ?) ON DUPLICATE KEY UPDATE a_session = ?"] at /usr/share/perl5/CGI/Session/Driver/mysql.pm line 50.: /usr/share/koha/opac/cgi-bin/opac/opac-main.pl [Fri Jun 02 18:18:35.522767 2017] [cgi:error] [pid 23874] [client 180.76.15.11:24457] AH01215: [Fri Jun 2 18:18:35 2017] opac-main.pl: DBD::mysql::db do failed: Table 'koha_library.sessions' doesn't exist [for Statement "INSERT INTO sessions (id, a_session) VALUES(?, ?) ON DUPLICATE KEY UPDATE a_session = ?"] at /usr/share/perl5/CGI/Session/Driver/mysql.pm line 50.: /usr/share/koha/opac/cgi-bin/opac/opac-main.pl [Fri Jun 02 18:18:35.535631 2017] [cgi:error] [pid 23874] [client 180.76.15.11:24457] AH01215: [Fri Jun 2 18:18:35 2017] opac-main.pl: DBD::mysql::db do failed: Table 'koha_library.sessions' doesn't exist [for Statement "INSERT INTO sessions (id, a_session) VALUES(?, ?) ON DUPLICATE KEY UPDATE a_session = ?"] at /usr/share/perl5/CGI/Session/Driver/mysql.pm line 50.: /usr/share/koha/opac/cgi-bin/opac/opac-main.pl gmasters@server1:/var/log/koha/library$ tail -10 *intranet-error.log* [Thu Jun 01 22:27:16.241162 2017] [cgi:error] [pid 19626] [client 127.0.0.1:52832] AH01215: [Thu Jun 1 22:27:16 2017] mainpage.pl: DBD::mysql::st execute failed: Table 'koha_library.sessions' doesn't exist [for Statement "SELECT a_session FROM sessions WHERE id=?" with ParamValues: 0='43d20a030010c2dd2acbec1552cd3252'] at /usr/share/perl5/CGI/Session/Driver/DBI.pm line 72.: /usr/share/koha/intranet/cgi-bin/mainpage.pl, referer: http://library-intra.oclibsys.org/ [Thu Jun 01 22:27:16.241441 2017] [cgi:error] [pid 19626] [client 127.0.0.1:52832] AH01215: [Thu Jun 1 22:27:16 2017] mainpage.pl: Can't call method "param" on an undefined value at /usr/share/koha/lib/C4/Auth.pm line 829.: /usr/share/koha/intranet/cgi-bin/mainpage.pl, referer: http://library-intra.oclibsys.org/ [Thu Jun 01 22:34:05.073353 2017] [cgi:error] [pid 20174] [client 127.0.0.1:52964] AH01215: [Thu Jun 1 22:34:05 2017] mainpage.pl: DBD::mysql::st execute failed: Table 'koha_library.sessions' doesn't exist [for Statement "SELECT a_session FROM sessions WHERE id=?" with ParamValues: 0='43d20a030010c2dd2acbec1552cd3252'] at /usr/share/perl5/CGI/Session/Driver/DBI.pm line 72.: /usr/share/koha/intranet/cgi-bin/mainpage.pl, referer: http://library-intra.oclibsys.org/ [Thu Jun 01 22:34:05.073612 2017] [cgi:error] [pid 20174] [client 127.0.0.1:52964] AH01215: [Thu Jun 1 22:34:05 2017] mainpage.pl: Can't call method "param" on an undefined value at /usr/share/koha/lib/C4/Auth.pm line 829.: /usr/share/koha/intranet/cgi-bin/mainpage.pl, referer: http://library-intra.oclibsys.org/ [Thu Jun 01 22:36:36.662060 2017] [cgi:error] [pid 20607] [client 127.0.0.1:52972] AH01215: [Thu Jun 1 22:36:36 2017] mainpage.pl: DBD::mysql::st execute failed: Table 'koha_library.sessions' doesn't exist [for Statement "SELECT a_session FROM sessions WHERE id=?" with ParamValues: 0='43d20a030010c2dd2acbec1552cd3252'] at /usr/share/perl5/CGI/Session/Driver/DBI.pm line 72.: /usr/share/koha/intranet/cgi-bin/mainpage.pl [Thu Jun 01 22:36:36.664142 2017]sessions [cgi:error] [pid 20607] [client 127.0.0.1:52972] AH01215: [Thu Jun 1 22:36:36 2017] mainpage.pl: DBD::mysql::db do failed: Table 'koha_library.sessions' doesn't exist [for Statement "INSERT INTO sessions (id, a_session) VALUES(?, ?) ON DUPLICATE KEY UPDATE a_session = ?"] at /usr/share/perl5/CGI/Session/Driver/mysql.pm line 50.: /usr/share/koha/intranet/cgi-bin/mainpage.pl [Thu Jun 01 22:36:40.221562 2017] [cgi:error] [pid 20607] [client 127.0.0.1:52972] AH01215: [Thu Jun 1 22:36:40 2017] mainpage.pl: DBD::mysql::st execute failed: Table 'koha_library.sessions' doesn't exist [for Statement "SELECT a_session FROM sessions WHERE id=?" with ParamValues: 0='8c7da8630f56ffbaee6374f6f60838c1'] at /usr/share/perl5/CGI/Session/Driver/DBI.pm line 72.: /usr/share/koha/intranet/cgi-bin/mainpage.pl, referer: http://library-intra.oclibsys.org/ [Thu Jun 01 22:36:40.221834 2017] [cgi:error] [pid 20607] [client 127.0.0.1:52972] AH01215: [Thu Jun 1 22:36:40 2017] mainpage.pl: Can't call method "param" on an undefined value at /usr/share/koha/lib/C4/Auth.pm line 829.: /usr/share/koha/intranet/cgi-bin/mainpage.pl, referer: http://library-intra.oclibsys.org/ [Fri Jun 02 14:36:37.463768 2017] [cgi:error] [pid 17602] [client 205.174.240.239:4037] AH01215: [Fri Jun 2 14:36:37 2017] mainpage.pl: DBD::mysql::db do failed: Table 'koha_library.sessions' doesn't exist [for Statement "INSERT INTO sessions (id, a_session) VALUES(?, ?) ON DUPLICATE KEY UPDATE a_session = ?"] at /usr/share/perl5/CGI/Session/Driver/mysql.pm line 50.: /usr/share/koha/intranet/cgi-bin/mainpage.pl [Fri Jun 02 15:02:15.705523 2017] [cgi:error] [pid 18456] [client 64.74.215.150:40105] AH01215: [Fri Jun 2 15:02:15 2017] mainpage.pl: DBD::mysql::db do failed: Table 'koha_library.sessions' doesn't exist [for Statement "INSERT INTO sessions (id, a_session) VALUES(?, ?) ON DUPLICATE KEY UPDATE a_session = ?"] at /usr/share/perl5/CGI/Session/Driver/mysql.pm line 50.: /usr/share/koha/intranet/cgi-bin/mainpage.pl gmasters@server1:/var/log/koha/library$ tail -10 *zebra-error.log* 20170529 07:35:21 library-koha-zebra: client (pid 30802) killed by signal 15, stopping 20170531 07:35:16 library-koha-zebra: client (pid 2067) killed by signal 15, stopping 20170531 07:35:57 library-koha-zebra: client (pid 28285) killed by signal 15, stopping I am not sure if the two errors in the logs are related. Was the sessions table introduced at a later time (after version 3.22 and before 16.11)? My backup on 4-26-2017 does not include a sessions table. This was the backup I performed before upgrading to 16.11 Rev. George Masters Director Orthodox Christian Library System 408.242.4632