*Hi everyone,* *I am using koha version 17.11 with the database Mysql ver15.11 distribution 10.0.36-MariaDB. I want to "**check in" and the error message below appears, I click on about page and the second information about data problems comes out. Please what can I do. I have limited knowledge with mysql and MariaDB.* *Thanks a lot.* *Check in error message message* 037655: Computer Science <http://154.68.225.19:8001/cgi-bin/koha/catalogue/detail.pl?type=intra&biblionumber=136> *The item has not been checked in due to a configuration issue in your system. You must ask an administrator to take a look at the about page <http://154.68.225.19:8001/cgi-bin/koha/about.pl#sysinfo> and search for the "data problems" section* Top of Form About page information Data problems Some of your tables have problems with their auto_increment values which may lead to data loss. *You should not ignore this warning.* The problem is that InnoDB does not keep auto_increment across SQL server restarts (it is only set in memory). So on server startup the auto_increment values are set to max(table.id)+1. To know how to avoid this problem see the related wiki page: DBMS auto increment fix <https://wiki.koha-community.org/wiki/DBMS_auto_increment_fix> Problems found Patrons The following ids exist in both tables *borrowers* and *deletedborrowers*: 4 Checkouts The following ids exist in both tables *issues* and *old_issues*: 16, 17, 18 Warnings regarding the system configuration *Preferences and parameters* *Warning* You are missing the <template_cache_dir> entry in your koha-conf.xml file. That will bring a performance boost to enable it.