This error indicates that your organization has a custom validation rule in place that is interfering with the insertion / update of a record. If you are encountering this error and believe you shouldn't be based on the circumstances, please contact your Salesforce Administrator to track down the problematic validation rule and adjust the criteria to allow for the insertion / update of the record you're working with.

For example, if you are encountering a validation error upon editing a case, check your validation rules on the Case object by navigating to Setup | Object Manager | Case | Validation Rules. You'll want to match up the text following "FIELD_CUSTOM_VALIDATION_EXCEPTION" to see which validation rule is causing the problem. (i.e. if the error you encounter reads "FIELD_CUSTOM_VALIDATION_EXCEPTION: Placing a case on-hold requires a follow-up date", you'll want to check the validation rules listed under the Case object to see which one contains the error "Placing a case on-hold requires a follow-up date".)


Email to Case Premium

If you are encountering this error during inbound email processing, you may consider adjusting your validation criteria to disregard updates made by your Email to Case Premium Context User.

Case Merge Premium

If you are encountering this error during merging (or unmerging), you may consider adjusting your validation rule criteria to utilize the "Merged By" and "Merged Date/Time" fields. These fields are set on child cases during a merge operation, and will be populated prior to validation rules running. Additionally, these field values are cleared prior to validation rules running during an unmerge.


For additional tips / tricks for configuring validation rules, please see the following articles:

https://help.salesforce.com/articleView?id=fields_validation_rules_tips.htm&type=5
https://trailhead.salesforce.com/en/modules/point_click_business_logic/units/validation_rules


Note: Vicasso support may be able to help identify problematic validation rules, but cannot provide direct assistance in updating the criteria of the validation rule. For more information on what is covered under the scope of support, please see the following knowledge article.

This is the expected behavior of Salesforce validation rules and is by design.

http://success.salesforce.com/ideaView?id=08730000000BrN2AAK