Prior to cPanel & WHM version 11.50,  Horde user data was stored in a single server-wide MySQL database. However, in 11.50, cPanel moved these data to individual SQLite database for each cPanel account.

Recently, during the upgrade, several users are seeing this failure message :

While attempting to back up Horde database, mysqldump did not exit cleanly: 2

For more information about the exact nature of the failure, review the /var/cpanel/logs/horde_mysqltosqlite_log file. cPanel & WHM versions 11.50 and later require SQLite for Horde data storage. Any Horde data that the system could not migrate is not visible to Horde users.

Review the log file as mentioned and see if the entire conversion has failed.

The command to perform the conversion in full on a server that did not get a chance to begin the conversion would be :

# /scripts/horde_mysqltosqlite

If you encounter a server that has been partially completed according to the output of the conversion process  /var/cpanel/logs/horde_mysqltosqlite_log , then it can be performed for a single user as per the logs using the following command :

# /usr/local/cpanel/3rdparty/bin/perl -MCpanel::Horde::MySQLToSQLite -e 'Cpanel::Horde::MySQLToSQLite->new->convert_user("cpanelaccountname")'

Replace ‘cpanelaccountname‘ with the concerned cpanel account name viewed from the logs !