Scenario 1 - UI

1. Perform the following query in JIRA's database, then take note of the custom fields returned;

   SELECT 
   	c.cfname AS "Custom Field",
   	o.customvalue AS "Value"
   FROM
   	customfield c
   	JOIN customfieldoption o ON c.id = o.customfield 
   WHERE
   	customvalue IS NULL;

2. Go to Administration > Issues > Custom Field;
3. Click Configure on the right of each custom field returned by the query above;

4. Delete any null option;

Scenario 1 - Database

1. If the above fails to resolve the issue, proceed with the deletion of the null value directly on the database. For that, use the following query:

   DELETE FROM customfieldoption WHERE customvalue is null;

2. Restart JIRA for changes to take effect.

Scenario 2

1. Perform the following query on JIRA's database to check if there are invalid entries on the customfieldoption table;

   SELECT
   	customfield
   FROM
   	customfieldoption
   WHERE
   	customfield NOT IN (
   		SELECT 
   			id
   		FROM
   			customfield
   		);

2. If the above query returns any result, run the query below;

   DELETE
   FROM
   	customfieldoption
   WHERE
   	customfield NOT IN (
   		SELECT
   			id
   		FROM
   			customfield
   		);

3. Restart JIRA for changes to take effect.