Unable to access Horde webmail after upgrading Plesk: Base table or view not found: 1051 Unknown table

Symptoms

• After a Plesk upgrade, it is not possible to access Horde webmail with the following error message in a web-browser:

  PLESK_INFO: Base table or view not found

• The following error messages appear in the Horde logfile /var/log/psa-horde/psa-horde.log:

  CONFIG_TEXT: HORDE [horde] SQL QUERY FAILED: SQLSTATE[42S02]: Base table or view not found: 1146 Table 'horde.rampage_types' doesn't exist
  SELECT type_id, type_name FROM `rampage_types` WHERE type_name IN
  ('calendar','event') [pid 54636 on line 815 of "/usr/share/psa-pear/pear/php/Horde/Db/Adapter/Base.php"]
  Base table or view not found: 1051 Unknown table 'horde_vfs_seq'
  Base table or view not found: 1051 Unknown table 'horde_muvfs_seq'
  Base table or view not found: 1051 Unknown table 'kronolith_shares_seq'
  Base table or view not found: 1051 Unknown table 'kronolith_resources_seq'

  OR

  CONFIG_TEXT: HORDE [horde] SQLSTATE[42S22]: Column not found: 1054 Unknown column 'attribute_color' in 'field list' [pid 21827 on line 1601 of "/usr/share/psa-pear/pear/php/Horde/Registry.php"]

• The following messages appear in the Plesk Installer logfile /var/log/plesk/install/autoinstaller3.log:

  CONFIG_TEXT: Trying to upgrade Horde webmail configuration...
  Unable to upgrade 'horde' to the latest version, since its configuration is in broken state. Run bootstrapper repair to fix. Some problems are found during upgrade Horde webmail configuration(see log file: /tmp/plesk_11.5.30_installation.log) tac: write error
  
  ERROR while trying to act on PEAR packages - description directory is not specified or does not exist

Cause

The database of Horde webmail is corrupted.

Resolution

1. Connect to the Plesk server via SSH.

2. For security reasons, create a backup of the Horde database:

   # MYSQL_PWD=`cat /etc/psa/.psa.shadow` mysqldump -u admin horde > /root/horde_dump.sql

3. Reinstall Horde using this KB article.