Custom Field not available in the Mass Update Fields Tab

 

1.  Navigate to Setup > Customization > select the appropriate field (e.g. Entity Field)

2. Edit the Custom Field that does not appear in the Mass Update Fields tab

3. Store Value = T

4. Save

5. Navigate back to Lists > Mass Update > Mass Updates > General Updates > Customer

6. Mass Update Fields tab > Custom field is now available for Mass Update

Note: Take extra precaution before altering any changes in the custom field settings as existing data may be erased or the field will cease from from functioning correctly.