Just a disclaimer, Always back up your data before performing any modifications to the database. Please test any alter, insert, update, or delete SQL commands on a staging server first and then proceed to production

• Take a database backup (preferably using native tools by involving your DBA)
• Note down the Active directory name

  select * from cwd_directory;
  

• Fetch the inactive users without an email address from the database

  select * from cwd_user 
  where directory_id in (select id from cwd_directory where directory_name = '________') -- Add the directory_name from above SQL output
  and active = 0 ;

• Verify if the above SQL returns the correct number of rows and the below the columns are empty

  lower_email_address
  email_address

• Run the update for a single user for testing purpose

  update cwd_user
  set lower_email_address = 'dummy@dummy.com', email_address = 'dummy@dummy.com'
  where directory_id in (select id from cwd_directory where directory_name = '________') -- Add the directory_name from above SQL output
  and active = 0 
  and lower_user_name = '________'; -- Pick any sample inactive user from above SQL output

• If the update works as expected for one row, formulate this SQL with a unique email address for all users and execute it (below is an example)

  -- Update another user's email address to dummy1@dummy.com
  update cwd_user
  set lower_email_address = 'dummy1@dummy.com', email_address = 'dummy1@dummy.com'
  where directory_id in (select id from cwd_directory where directory_name = '________') -- Add the directory_name from above SQL output
  and active = 0 
  and lower_user_name = '________'; -- Pick any sample inactive user from above SQL output
  -- Update another user's email address to dummy2@dummy.com
  update cwd_user
  set lower_email_address = 'dummy2@dummy.com', email_address = 'dummy2@dummy.com'
  where directory_id in (select id from cwd_directory where directory_name = '________') -- Add the directory_name from above SQL output
  and active = 0 
  and lower_user_name = '________'; -- Pick any sample inactive user from above SQL output

• Restart Jira to see the database changes in the Jira UI

Additional info

Please use this in your staging environment, for your reference only to generate bulk update statements if there are many users (modify the count per need)

count=60
for((i=1;i<=count;i++))
do
   echo $ 'update cwd_user set lower_email_address = '"'"'dummy'$i'@dummy.com'"'"', email_address = '"'"'dummy'$i'@dummy.com'"'"' where directory_id!=1 and active = 0 and email_address = '"'"' '"'"';'
done

To temporarily install Crowd and sync these inactive users:

• LDAP user is in inactive status with a blank email address
  
• Connect the Crowd Server to Jira
• Create an inactive user in Crowd (ensure to have the exact similar username, in this e.g. it is ABC)
  
• Add the required groups in Crowd
• Perform a synchronization in Jira against the Crowd server
• Switch the user directories to the top order
  
• This user now belongs to Crowd (with a dummy email address)
  

 Please cross-verify if the user history is retained across after switching directories 

How to bulk update users email addresses in JIRA using REST API