Problem

Crowd will not start up after an upgrade. The following appears in the atlassian-crowd.log

2016-09-21 22:30:20,348 localhost-startStop-1 INFO [crowd.upgrade.tasks.UpgradeTask645IntroduceUserPermissions] Group mapping for '<somegroup>' is being added in directory 'somedirectory'
2016-09-21 22:30:20,452 localhost-startStop-1 WARN [engine.jdbc.spi.SqlExceptionHelper] SQL Error: 1062, SQLState: 23000
2016-09-21 22:30:20,453 localhost-startStop-1 ERROR [engine.jdbc.spi.SqlExceptionHelper] Duplicate entry '<somegroup>' for key 'app_dir_mapping_id'
2016-09-21 22:30:20,454 localhost-startStop-1 ERROR [jdbc.batch.internal.BatchingBatch] HHH000315: Exception executing batch [could not perform addBatch]

Diagnosis

Diagnostic Steps

Run the following SQL query to see all the groups in your Crowd instance. 

SELECT d.directory_name, g.group_name, COUNT(lower_user_name) FROM cwd_user u
LEFT JOIN cwd_membership m
ON u.id = m.id
LEFT JOIN cwd_directory d
ON u.directory_id = d.id
LEFT JOIN cwd_group g
ON u.directory_id = g.directory_id
GROUP BY d.directory_name, g.group_name
ORDER BY d.directory_name;
SELECT * FROM cwd_group;
SELECT * FROM cwd_directory;

Cause

This error occurs when the default 'crowd-administrator' group does not exist in the Crowd internal directory or another internal directory that was created. A new admin group was created in the internal directory. The upgrade is trying to duplicate the group and errors. 

Workaround

You can workaround this issue by following the steps below: 

1. Add a temporary Crowd administrator group into all of your internal directories where it does not exist. Name it 'crowd-administrators'.
2. Assign all of the existing 'admin (role) group members to this newly created crowd-administrators group.
3. Add this group to each of your Atlassian Applications, as necessary.
4. Delete the problematic _admin_ group from your Crowd instance. This group is identified in the error above. 
5. Reattempt the upgrade process.

6. Once you've successfully upgraded, you can execute the following SQL queries to rename back the temporary group to _admin (role) _ as desired:

   UPDATE cwd_group 
   SET group_name = 'System Administrator'
   WHERE group_name = 'crowd-administrators';
   
   UPDATE cwd_group 
   SET lower_group_name = 'system administrator'
   WHERE lower_group_name = 'crowd-administrators';
   
   UPDATE cwd_app_dir_group_mapping 
   SET group_name = 'System Administrator'
   WHERE group_name = 'crowd-administrators';
   
   UPDATE cwd_membership 
   SET parent_name = 'System Administrator'
   WHERE parent_name = 'crowd-administrators';
   
   UPDATE cwd_membership 
   SET lower_parent_name = 'system administrator'
   WHERE lower_parent_name = 'crowd-administrators';