There isn’t a way to flag or black list certain customers in QuickBooks Online. I encourage you to send feedback about this: http://feedback.qbo.intuit.com/. You can use this page to voice your feedback, request features and vote on what you’d like to see. You can even see any progress on new features.

Resolution for 'black flag issue: 'Is there a way to black flag or black list certain customers?' available: Yes.

The black flag issue or error code is a known issue in Quickbooks Online (QBO) and/or Quickbooks. Support for this issue is available either by self-service or paid support options. Experts are available to resolve your Quickbooks issue to ensure minimal downtime and continue running your business. First try to resolve the black flag issue yourself by looking for a resolution described in the article. If it is a complex black flag issue or you are unable to solve the issue, you may contact us by clicking here or by using other black flag support options.

For more information about resolving issues related to black flag in Quickbooks/QBO or to get support for the issue 'Is there a way to black flag or black list certain customers?', click the link below: